Chronic Wasting Disease (CWD) and Government Response Congressional Research Service May 17, 2019
May 17, 2019
Chronic Wasting Disease (CWD) and Government Response
Chronic wasting disease (CWD) is a degenerative neurological disorder that affects cervids, including multiple species of deer, elk, and moose. Infected cervids may exhibit many symptoms including weight loss or wasting, poor balance, excessive salivation, difficulty swallowing, and others. CWD has a 100% mortality rate. The spread of CWD has impacted both wild and captive animals, including farm-raised cervids (e.g., for venison production), across the United States. CWD has caused economic losses for U.S. farm-raised cervid operations and may affect wild cervids. As a result, Congress is taking an active interest in the incidence and management of CWD. CWD was first discovered in 1967 in Colorado, and since that time, it has spread across the United States. It may be transmitted by direct animal-to-animal contact or indirectly when animals come in contact with infected substances, such as soil, dust, or forage. According to the U.S.
Geological Survey (USGS), CWD has spread to 26 U.S. states (as of May 2019; Figure 1) and to Canada, Finland, Norway, Sweden, and South Korea.
CWD is a type of transmissible spongiform encephalopathy (TSE) that affects cervids. TSEs, also known as prion diseases, are a group of degenerative neurological disorders that result in a spongy appearance of the infected brain. TSEs are believed to be caused by abnormally folded prion proteins. Prion proteins are naturally occurring but, when folded incorrectly, can become both infectious and deadly. Other TSEs include scrapie, which afflicts sheep and goats, and bovine spongiform encephalopathy (BSE, also known as mad cow disease), which affects cattle. TSEs in humans include Creutzfeldt-Jakob disease.
After infection by CWD, cervids may not exhibit symptoms for an extended period following exposure. This incubation period can last for a year or longer. No vaccine or treatment exists for CWD. Two diagnostic post-mortem testing techniques exist for identifying CWD in cervids.
In some experimental studies, CWD has been shown to infect mice, squirrels, monkeys, and potentially macaques.
According to the Centers for Disease Control and Prevention (CDC) in the Department of Health and Human Services (HHS), there is no “strong evidence,” to date, of CWD infecting humans. It is unknown if humans may become infected by CWD prions, but some research suggests that CWD may possibly pose a risk to humans. As a precaution, the CDC and other public health officials advise caution in handling/processing animals that may be infected and warn against eating meat from an infected cervid. The CDC monitors current research on the potential for CWD transmission to humans and provides recommendations for hunters to reduce their risk of exposure.
CWD Management Activities
CWD management activities are shared by several federal and state departments and agencies. The primary federal agencies include the Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture (USDA) and USGS, the U.S. Fish and Wildlife Service (FWS), and the National Park Service (NPS) within the Department of the Interior (DOI). Various state agencies— such as those overseeing agriculture, fish, or wildlife— often collaborate with federal agencies. Over 25 states have control programs for both wild and captive cervids. An early example of state and federal government cooperation was the “CWD Task Force” (no longer in operation). Initiated in 2002 by USDA, DOI, several state wildlife and agriculture agencies, land grant universities,
Figure 1. Distribution of CWD in North America Source: CRS, adapted from USGS, National Wildlife Health Center, https://www.usgs.gov/centers/nwhc/science/expanding-distributionchronic-wasting-disease?qt-science_center_objects=0#qt-science_center_objects. Notes: Map depicts the distribution area of CWD in North America as of May 2019. This map is regularly updated by the USGS. Both Hawaii and Alaska (not depicted in the figure) do not have cases of CWD. Chronic Wasting Disease (CWD) and Government Response www.crs.gov | IF11213 · VERSION 1 · NEW
and other organizations, the purpose of the task force was to establish a network to conduct CWD surveillance, research, and depopulation/culling efforts. Some notable outcomes of the task force include the publication of a management plan—titled “Plan for Assisting States, Federal Agencies, and Tribes in Managing Chronic Wasting Disease in Wild and Captive Cervids”—and a USGS-led CWD data clearinghouse. Today, cooperation continues among state and federal agriculture and wildlife agencies, producers, and hunters.
Federal Management Activities
At the federal level, many CWD activities are within the purview of USDA’s APHIS. One of APHIS’s goals is to eradicate animal diseases, such as CWD from farmed deer and elk herds, and to assist states and tribes in managing diseases in wild animals. APHIS’s legislative authority for this work derives mainly from the Animal Health Protection Act (AHPA, 7 U.S.C. §§8301 et seq.).
One APHIS management tool is the CWD Voluntary Herd Certification Program (HCP), which provides a national approach to the control of CWD in farm-raised cervids. The program is a voluntary, cooperative effort among APHIS, state animal health and wildlife agencies, and farming operations. As of September 2018, 28 states are participating in this voluntary program. APHIS coordinates with state agencies to encourage cervid owners to certify their herds and comply with the CWD HCP standards to prevent the introduction and spread of CWD (9 C.F.R. Parts 55 and 81). To be enrolled in CWD HCP, herd owners are required to install fencing, provide individual animal identification, and conduct post-mortem testing for all animals over 12 months that die for any reason.
Several DOI agencies have also been involved in CWD activities, including USGS, FWS, and NPS. USGS, primarily through its National Wildlife Health Center, collaborates with other federal and state agency partners to address such challenges as the need for new diagnostic capacities as well as data collection. FWS has addressed CWD through a number of mechanisms, including through law enforcement, requiring mandatory testing in certain areas, and developing CWD plans for individual units in the National Wildlife Refuge System. NPS has similarly addressed CWD, including through the NPS Wildlife Health Branch, research activities, and management and surveillance efforts.
Animal feed, as well as rendered or animal byproducts, and wild game meat—including venison—intended for retail sale fall under the purview of HHS’s Food and Drug Administration (FDA). The Food Safety and Modernization Act (P.L. 111-353) provides FDA authority to establish preventative controls (e.g., food safety plans) for animal feed intended to be consumed by livestock and other animals, including farm-raised cervids. In 2016, FDA issued guidance to the industry prohibiting the use of materials from deer and elk in any animal feed or feed ingredients. In addition, FDA inspects and regulates all non-USDA-regulated meats and meat products, including wild or captive cervid meat, intended for commercial sale.
State Management Activities
State government management activities include enforcing APHIS’s CWD regulations for wild/captive cervids, establishing state-specific CWD regulations, and conducting CWD testing in wild/captive cervids. In some states, the department of agriculture has jurisdiction over captive and wild cervids. In other states, the fish and game department has this responsibility. In several states, these two departments share this responsibility. The Environmental Protection Agency coordinates with states to develop protocols for the safe disposal of potentially infected animal carcasses.
In October 2018, the Michigan Department of Natural Resources released an analysis of CWD regulations in the United States and Canada. The analysis reports on statespecific responses to managing CWD. For example, many states prohibit cervid imports from any country, region, or state in which CWD is found and/or require that the country, region, or state exporting the cervid be enrolled in an official CWD monitoring or certification program. Many states have banned all cervid and cervid product imports.
Recent Congressional Interest
In the 115th Congress, the Agriculture Improvement Act of 2018 (P.L. 115-334, commonly referred to as the 2018 farm bill) included a provision (Section 7209) to make CWD research and extension grants a high priority. The 116th Congress appropriated funds to address CWD in wild and captive cervids through the Consolidated Appropriations Act, 2019 (P.L. 116-6). In particular, both APHIS and the Agricultural Research Service, also in USDA, were specifically directed to address CWD (H.Rept. 116-9). Some Members of Congress have also introduced legislation to continue CWD research, surveillance, and management. For example, bills introduced in the 116th Congress related to CWD include the following.
The CWD Transmission in Cervidae Study Act (H.R. 837 and S. 382) would authorize a special study on the spread of CWD in cervids. The bill directs APHIS to study CWD in wild, captive, and farm-raised cervid populations no later than six months after the date on which funds are made available.
The CWD Disease Management Act (H.R. 1550 and S. 689) would authorize $35 million of appropriations for state and tribal efforts to manage and control CWD.
The ACCESS Act (H.R. 1326) includes two titles (Titles X and XI) that incorporate CWD oversight that are similar to the CWD Transmission in Cervidae Study Act and CWD Disease Management Act.
The DEER Act (S. 613 and H.R. 1919) would amend the AHPA to provide support for states and coordinate response efforts to address CWD through a multiagency task force. The bill would also award a grant for research focused on CWD in whitetail deer. Sahar Angadjivand, sangadjivand@crs.loc.gov, 7-1286 R. Eliot Crafton, rcrafton@crs.loc.gov, 7-7229 IF11213
-----Original Message-----
From: Terry Singeltary
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Sent: Mon, Oct 7, 2019 12:02 pm
Subject: re-Chronic Wasting Disease (CWD) and Government Response
re-Chronic Wasting Disease (CWD) and Government Response
From: Terry Singeltary
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Cc: rcrafton
Sent: Mon, Oct 7, 2019 12:02 pm
Subject: re-Chronic Wasting Disease (CWD) and Government Response
May 17, 2019
https://fas.org/sgp/crs/misc/IF11213.pdf
Subject: MSU SCIENTISTS ARE TESTING A FASTER WAY TO DETECT CHRONIC WASTING DISEASE
Pathogens. 2017 Sep; 6(3): 35. Published online 2017 Aug 5. doi: 10.3390/pathogens6030035 PMCID: PMC5617992 PMID: 28783058
Subject: MSU SCIENTISTS ARE TESTING A FASTER WAY TO DETECT CHRONIC WASTING DISEASE
Published: Sept. 30, 2019
MSU SCIENTISTS ARE TESTING A FASTER WAY TO DETECT CHRONIC WASTING DISEASE
Contact(s): Emily Lenhard
Michigan State University and Michigan Department of Natural Resources scientists are testing a faster, more accurate way to screen and diagnosis chronic wasting disease, or CWD, in deer. The three-year, $900,000 project, funded by both institutions, will use RT-QuIC, a technology known to have better detection and sensitivity in real time.
The current technology used for CWD screening and diagnosis is slow, sometimes less sensitive and testing must take place in a lab, which can be labor-intensive.
Srinand Sreevatsan, professor and associate dean of research and graduate studies in the MSU College of Veterinary Medicine, Kelly Straka, section supervisor and laboratory scientist for the MDNR Wildlife Disease Laboratory, Rachel Reams, director of the MSU Veterinary Diagnostic Laboratory, and Steve Bolin, professor in the Department of Pathobiology and Diagnostic Investigation, will lead the trial.
“We have a unique opportunity to use the experience of the DNR and MSU on the biology of CWD and in test development, as well as access to samples and current ‘gold standard tests’ to create a new solution for CWD screening and testing,” Reams said.
According to Sreevatsan, CWD is a prion disease, which is a family of diseases that starts with an accumulation of abnormally foldedproteins in the brain and can lead to neurological damage.
“We are going to use RT-QuIC to amplify the misfolded protein in suspect tissue samples,” Sreevatsan said. “This will offer us better detection and sensitivity as these proteins accumulate.”
Another aspect of this study is to detect biomarkers that accumulate in blood, as a result of neurological damage, as a screening test in the field. This approach would facilitate deer screening in the field for the neuronal proteins. That means testing will be fast and easy for captive deer farmers and wild deer hunters, and only deer triggering positive for potential brain damage would be sent to the laboratory for RT-QuIC testing.
This is especially important because clinical signs of CWD don’t show up until the later stages of the disease – after the infected deer has had plenty of opportunity to spread the disease to other animals. The new protocol would encourage testing to protect animal health, as well as provide faster data for health officials and natural resource protection agencies to help slow the spread of CWD in the environment.
“This is a conservation effort,” Sreevatsan said. “We want to protect our environment and the animals who live in it, as well as the tradition of hunting.”
During the first year of the project, scientists will develop RT-QuIC and investigate the specific biomarkers that indicate CWD. They will use these results to develop a rapid field test to detect CWD in free-ranging and hunted deer during the second and third year.
Rachel Reams is the director of the MSU Veterinary Diagnostic Laboratory and is part of an effort to find a faster, more accurate way to screen and diagnosis chronic wasting disease, or CWD, in deer. Courtesy photo.
199. CHRONIC WASTING DISEASE TRANSMISSION STUDIES TO NON-HUMAN PRIMATES AND TRANSGENIC MICE
Brent Race, Katie Williams, Christina D. Orrù, Andrew G. Hughson, Lori Lubke and Bruce Chesebro
National Institute of Allergy and Infectious Diseases, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, Hamilton, MT, USA CONTACT Brent Race raceb@niaid.nih.gov
ABSTRACT
Introduction: Chronic wasting disease (CWD) is the only prion disease affecting free-ranging animals, reported in North America, South Korea and Norway. Unlike in most other prion disease CWD agents are shed in blood, urine and feces which most likely contribute to the horizontal transmission between cervid species. The developments of amplification-based seeding assays have been instrumental in the detection of low levels of prions in clinical samples. Using real-time quaking-induced conversion (RT-QUIC), we established an ultrasensitive detection method for PrPCWD in the urine from CWD-infected sequentially sampled transgenic mice overexpressing elk prion protein (TgElk mice). In addtion, RT-QUIC was performed in the kidney and brain of theses mice model to trace abnormal prion. Materials and Methods: 44 brain and kidney, urine samples from sequentially collected from CWD-infected TgElk mice (TgElk CWD) were stored at -80℃. In brain and kidney, 10% (w/v) homogenate was prepared in 0.9% sterilized saline. In urine 100uL of each sample was mixed with 10uL 2.8% sodium phosphotungustic acid (NaPTA) and incubated for 1hr at 37℃ with shaking at 1,350 rpm. Samples were centrifuged for 30min at 16,100g. The pellet was resuspended in 10uL of 0.1% SDS/PBS for 30min at 55℃. RT-QUIC reactions were set up in 96-well clear bottom optic plates and consisted of 98uL RT-QUIC buffer [final concentrations of 1XPBS, 1mM EDTA, 10uM Thioflavin, 300mM NaCl buffer and 0.1mg/ml recombinant Syrian hamster recombinant protein (23-231) and 2uL of sample. The RT-QUIC assay was performed on a FLUOstar Omega fluorescence plate reader that was preheated to 42℃ for 60hr with 90sec shaking at 700rpm followed by 1min incubation. Results: Five randomly selected mice were sequentially culled on every 15 days from 30dpi to 120dpi during CWD infected TgElk mice reached terminal stage. Rough hair coats among clinical signs were showed from 90 dpi. PrPCWD in the brain in TgElk CWD was detectable persistently from early stages (30dpi), and in the kidney PrPCWD was also detectable in clinical and terminal stages (90 dpi and 120dpi). PrPCWD in the urine in TgElk CWD reached the highest levels at 120dpi. NaPTA/RT-QUIC was applied to measure PrPCWD in urine samples collected on every 15 days from 30dpi to 120dpi when CWD infected TgElk mice reached terminal stage. PrPCWD in the urine in TgElk CWD reached the highest levels at 90dpi. PrPCWD was also detectable in late and terminal stages (120dpi). Conclusions: We demonstrate that CWD prions can be detected by RT-QUIC or NaPTA/RT-QUIC in the brain, kidney and urine of TgElk mice at the early and terminal stages of disease. Based on these data, we suggest that PrPCWD is excreted into only urine until 90 dpi and then slowly accumulated in kidney. Our results can be used in designing future study of CWD pathogenesis in TgElk mice.
KEYWORDS: Cynomolgus macaques; squirrel monkeys; non-human primate; transgenic mice; CWD; RT-QuIC; prion; cross-species transmission; barrier; chronic wasting disease
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209. COMPARATIVE ANALYSIS OF THE NEUROINVASION OF CHRONIC WASTING DISEASE STRAINS (WISC-1 AND H95+) IN TRANSGENIC MICE EXPRESSING DIFFERENT CELLULAR PRION PROTEINS
Danielle Gushuea, Camilo Duque Velásqueza, Chiye Kima, Judd Aikenb and Debbie McKenziea
aDepartment of Biological Sciences, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada; bDepartment of Agricultural, Food and Nutritional Sciences, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
CONTACT Danielle Gushue dgushue@ualberta.ca
ABSTRACT
Chronic wasting disease (CWD) is a contagious prion disease of free-ranging and captive cervids from North America, Scandinavia, and Korea. The transmission cycle of CWD among cervids relies on the lymphotropic nature of CWD prions and the environmental persistence of prion infectivity shed by affected animals. Multiple prion strains circulate in CWD enzootic areas and their diversity is modulated by disease transmission between cervids expressing different PrPC molecules. Prion strains neuroinvade with different efficiency and this process is dependent on the route of exposure, the infectious dose and the structural compatibility between prion conformation and host PrPC. To evaluate if the route of exposure affects strain adaptation, we compared the neuroinvasion properties of pure Wisc-1 strain and a mixture of this one with the H95+ strain. We previously demonstrated these strains have distinct biological properties, including conformational differences, brain targeting areas, and transmission host range. Two transgenic mouse lines expressing PrPC allelotypes, Q95G96 or Q95S96, were exposed either orally or intraperitoneally (IP) and the phenotypic properties produced by each strain-route-host combination were compared. Consistent with previous observations in host expressing wt PrPC, the Wisc-1 strain had higher disease penetrance and shorter incubation periods compared to the H95+. The intraperitoneal route was more efficient than the oral route, which lacked complete attack rates. The incubation period of Wisc-1 doubled compared to the intracranial (IC) route. Interestingly, the differences in incubation between the host exposed to Wisc-1 or the H95+ mixture were smaller than previously reported by IC route. The Wisc-1 host-specific titre in the H95+ mixture is at least two-fold lower than pure Wisc-1, suggesting the route of exposure influenced strain selection from the mixture. This also indicates Wisc-1 is highly adapted for neuroinvasion of deer expressing wt-PrPC. With the potential for new prion strains to emerge and the presence of multiple strains in a single host, it is important to characterize their transmission properties, including their capacity to neuroinvade and their tissue tropism.
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FRIDAY, OCTOBER 04, 2019
Inactivation of chronic wasting disease prions using sodium hypochlorite
Evolution of Diagnostic Tests for Chronic Wasting Disease, a Naturally Occurring Prion Disease of Cervids
Nicholas J. Haley1,* and Jürgen A. Richt2
THURSDAY, AUGUST 29, 2019
Detection of CWD in cervids by RT-QuIC assay of third eyelids
TUESDAY, JULY 30, 2019
Guidelines for reporting surveillance data on Transmissible Spongiform Encephalopathies (TSE) in the EU within the framework of Regulation (EC) No 999/2001 APPROVED: 9 July 2019
page 15 and 16;
The testing protocol for CWD in cervids when confirmatory testing is performed is shown in Figure 5.
aphis usda cwd
6. Diagnostics The regulatory authority for official CWD tests and laboratory approval is found in 9 CFR 55.8. 6.1
Testing Authority and Approved Laboratories
Testing Authority Laboratories will be approved by NVSL, as designated by the APHIS Administrator, to conduct official CWD testing in accordance with 9 CFR 55.8. All suspect positive test results must be confirmed by NVSL. Approved Laboratories Only laboratories that are members of the National Animal Health Laboratory Network (NAHLN) will be approved to conduct official CWD diagnostic testing. Requirements for laboratory approval and a list of laboratories approved to conduct CWD testing can be found on the NAHLN Web Site (https://www.aphis.usda.gov/animal_health/nahln/downloads/cwd_elisa_lab_list.pdf).
Not all laboratories are approved to perform all officially recognized types of CWD assays.
The VS Cervid Health staff, the NVSL Director, and the NAHLN Coordinator will maintain a list of officially recognized CWD assays and when appropriate the tissues approved for laboratories that conduct these tests for CWD.
The list will be available on request to all interested parties.
6.2 Official CWD Tests
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TUESDAY, OCTOBER 01, 2019
Genetic susceptibility to chronic wasting disease cwd tse prion?
i am concerned with the fact, the longer you can delay death with cwd, you risk having a cwd tse prion infected deer live longer in the wild or captive, thus giving more time to spread disease. you also risk developing a super cwd tse strain imo. we already have multiple strains, with what seems to be a super strain of cwd in Texas. also, with scrapie, they thought arr was resistant in sheep, until it was not...
Michigan State Legislators Turn To Draft Dodger Ted Nugent To Make Scientific Decisions over DNR on CWD TSE Prion
wow, Michigan legislators stoop to a new low, to help spread CWD, State Rep. Michelle Hoitenga of Manton, along with shitting his pants, draft dodging ted nugent, will try and overturn the DNR baiting ban so they can help spread cwd to hell and back. ted nugent cannot hunt and kill anything unless he hunts over a pile of bait, he is a convicted slob hunter, and he cares nothing about cwd tse prion, he is oblivious to the consequences of the cwd tse prion. so sad for Michigan to allow someone like ted nugent to dictate legislation for cwd tse prion over the DNR scientist. ...it's just unbelievable, imo...terry
Ted Nugent scheduled to testify in support of deer, elk baiting before Legislature
LANSING (WJRT) (9/16/2019) - Rocker Ted Nugent, a Michigan native and hunting enthusiast, is planning to testify in support of deer and elk baiting before a legislative committee on Tuesday.
He is joining State Rep. Michelle Hoitenga of Manton to support her bill that would overturn Michigan's current ban on deer and elk baiting. They will speak to the House Government Operations Committee at 9 a.m. in Lansing.
The Michigan Natural Resources Commission issued a baiting ban for deer and elk in August 2018. The ban is designed to limit the spread of chronic wasting disease.
Some animal experts believe deer and elk congregating at baiting sites can spread the deadly disease. Nugent and Hoitenga question the science behind those claims.
House Bill 4687 would allow baiting during open hunting seasons for deer and elk. Hoitenga describes her bill as halting the overregulation of hunting activity in the state.
stop baiting period. the congregation of cervid by unnatural means whether or not it’s a pile of corn or a field of planted lettuce and such, bottom line, you congregate cervid in one place, and over time, the shedding of the CWD TSE Prion will load up the environment, and given enough time, everything will be exposed or contaminated. this is science, not BS ted nugent is spreading.
it's your state, it's your choice, sound science, or some as wipe draft dodger, that has to have a pile of bait to hunt over, and cares nothing about cwd tse prion and ramifications there from...terry]
77. Assessing chronic wasting disease strain differences in free-ranging cervids across the United States
Kaitlyn M. Wagnera, Caitlin Ott-Connb, Kelly Strakab, Bob Dittmarc, Jasmine Battend, Robyn Piercea, Mercedes Hennessya, Elizabeth Gordona, Brett Israela, Jenn Ballarde and Mark D Zabela
aPrion Research Center at Colorado State University; bMichigan Department of Natural Resources; cTexas Parks and Wildlife Department; dMissouri Department of Conservation, 5. Arkansas Game and Fish Commission
CONTACT Kaitlyn M. Wagner miedkait@rams.colostate.edu
ABSTRACT
Background/Introduction: Chronic wasting disease (CWD) is an invariably fatal prion disease affecting captive and free-ranging cervids, including white-tailed deer, mule deer, moose, elk, and reindeer. Since the initial description of the disease in the 1960’s, CWD has spread to 23 states, 3 Canadian Provinces, South Korea, Norway and, most recently, Finland. While some outbreaks of CWD were caused by transport of infected animals from endemic regions, the origin of CWD in other epizootics is unclear and has not been characterized. Previous studies have shown that there are two distinct strains of CWD. However, the continuous spread and the unclear origin of several outbreaks warrant continued surveillance and further characterization of strain diversity.
Materials and Methods: To address these knowledge gaps, we used biochemical tests to assess strain differences between CWD outbreaks in Michigan, Texas, Missouri, and Colorado, USA. Brain or lymph node samples were homogenized and digested in 50 µg/mL proteinase K (PK). These samples were then run on a Western blot to assess glycoform ratio and electrophoretic mobility. Texas samples were digested in 100 µg/mL PK. To assess conformational stability, brain or lymph node homogenates were incubated in increasing concentrations of guanidine hydrochloride from 0 M to 4 M in 0.5 M increments. Samples were then precipitated in methanol overnight, washed and PK digested in 50 µg/mL PK before slot blotting.
Results: Our results have found significant differences in glycoform ratio between CWD from Michigan and Colorado, but no differences were observed in conformational stability assays. Interestingly, when testing our CWD isolates from Texas to analyse electrophoretic mobility and glycoform ratio, we found that these samples did not exhibit the characteristic band shift when treated with PK, but PK resistant material remained. Additionally, results from our conformational stability assay demonstrate a unique profile of these Texas isolates. Testing of samples from Missouri is currently underway.
Conclusions: Thus far, our data indicate that there are strain differences between CWD circulating in Michigan and CWD in Colorado and provide important insight into CWD strain differences between two non-contiguous outbreaks. We have also identified a unique strain of CWD in Texas with biochemical strain properties not seen in any of our other CWD isolates. These results highlight the importance of continued surveillance to better understand this devastating disease. These results have important implications for CWD emergence, evolution and our understanding of prion strain heterogeneity on the landscape.
TEXAS CWD TSE PRION STRAIN UNLIKE ANYTHING EVER SEEN
“Wow,” he said. “Unlike anything we've seen before.”
The prions from the Texas deer were a lot harder to destroy than the ones from the Colorado elk. In fact, the guanidine barely damaged them at all. “We’ve never seen that before in any prion strain, which means that it has a completely different structure than we've ever seen before,” says Zabel. And that suggests that it might be a very different kind of chronic wasting disease. The researchers ran the same test on another Texas deer, with the same results.
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“Wow,” he said. “Unlike anything we've seen before.”
The prions from the Texas deer were a lot harder to destroy than the ones from the Colorado elk. In fact, the guanidine barely damaged them at all. “We’ve never seen that before in any prion strain, which means that it has a completely different structure than we've ever seen before,” says Zabel. And that suggests that it might be a very different kind of chronic wasting disease. The researchers ran the same test on another Texas deer, with the same results.
Now, these are only the preliminary results from a few animals. Wagner and Zabel have a lot more experiments to do. But if future tests come to the same conclusion, it would support their hypothesis that there are multiple strains of chronic wasting disease out there, all with different origins. That, in turn, could mean that this disease will become even trickier to manage than it already is.
And, Zabel adds, there’s something else. “If it's still evolving, it may still evolve into a form that could potentially, eventually affect humans,” he says.
Zabel is not the only one worried about that possibility.
OSTERHOLM, THE EPIDEMIOLOGIST from Minnesota, is also concerned. He directs the Center for Infectious Disease Research and Policy at the University of Minnesota, and is serving a one-year stint as a “Science Envoy for Health Security” with the U.S. State Department. In February, he told Minnesota lawmakers that when it comes to chronic wasting disease, we are playing with fire. “You are going to hear from people that this is not going to be a problem other than a game farm issue. You're going to hear from people that it's not going to transmit to people, and I hope they're right, but I wouldn't bet on it,” he said. “And if we lose this one and haven’t done all we can do, we will pay a price.”
If that wasn’t warning enough, he added: “Just remember what happened in England.”
THURSDAY, SEPTEMBER 05, 2019
Unique Profile of The Texas CWD TSE Prion isolates, the TSE Prion CWD, Scrapie, BSE in Livestock, and CJD in Humans
SATURDAY, AUGUST 24, 2019
Michigan Chronic Wasting Disease CWD TSE Prion Two More Cases Total 122 To Date
Mineral licks as environmental reservoirs of chronic wasting disease prions
Ian H. Plummer,Chad J. Johnson,Alexandra R. Chesney,Joel A. Pedersen ,Michael D. Samuel
Abstract
Chronic wasting disease (CWD) is a fatal neurodegenerative disease of deer, elk, moose, and reindeer (cervids) caused by misfolded prion proteins. The disease has been reported across North America and recently discovered in northern Europe. Transmission of CWD in wild cervid populations can occur through environmental routes, but limited ability to detect prions in environmental samples has prevented the identification of potential transmission “hot spots”. We establish widespread CWD prion contamination of mineral licks used by free-ranging cervids in an enzootic area in Wisconsin, USA. We show mineral licks can serve as reservoirs of CWD prions and thus facilitate disease transmission. Furthermore, mineral licks attract livestock and other wildlife that also obtain mineral nutrients via soil and water consumption. Exposure to CWD prions at mineral licks provides potential for cross-species transmission to wildlife, domestic animals, and humans. Managing deer use of mineral licks warrants further consideration to help control outbreaks of CWD.
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DISCUSSION
Our results demonstrate that CWD-infected white-tailed deer deposit prions at mineral licks they visit. Although the mechanism of prion deposition is unknown, we suspect deposition of saliva by infected deer during ingestion of soil and water at mineral licks has the highest potential to facilitate indirect transmission to susceptible deer. Saliva from white-tailed deer infected with CWD contains on the order of 1–5 infectious doses (ID50) per 10 mL as quantified by real-time quaking-induced conversion, where an ID50 is the dose of CWD prions capable of infecting half of the transgenic mice expressing cervid prion protein [48]. Frequent visitation by infected cervids could allow mineral licks to become potential “hot spots” for indirect transmission of CWD [49]. Currently, little is known about the relative importance of direct contact and environmental routes of CWD transmission in free-ranging cervids [10]. Thus, how artificial and natural mineral licks contribute to current and future CWD infection in cervids and whether licks should be managed to control cervid use are important questions for further research.
Despite the relatively recent detection of CWD in Wisconsin (2001) and the moderate incidence of infection (6–19% prevalence in adult deer in the area sampled at the time of sample collection), our results suggest contamination of mineral licks in the CWD outbreak zone is widespread. This finding suggests that mineral licks may serve as reservoirs of CWD prions that contribute to disease transmission to susceptible animals. Although the levels of CWD prions in the samples analyzed appears low, we note that the association of prions with clay minerals often present at mineral licks can dramatically enhance disease transmission via the oral route of exposure [30–31]. For hamster-adapted scrapie prions binding to montmorillonite clay particles enhanced transmission by a factor of 680, however, an upper bound on the enhancement factor could not be assigned [30–31]. At present, the degree to which binding to clay mineral particles enhances CWD transmission to deer via the oral (or nasal) route of exposure is not known. Furthermore, repeated oral exposure to prions is associated with increased likelihood of disease transmission [50]. Differences in the sialyation status of N-linked glycans between brain-derived and secreted/excreted PrPCWD may impact oral infectivity [51]. Cervid species that avoid interspecific contact make use of the same mineral lick sites [49], potentially leading to interspecies transmission. Mineral licks also attract livestock and other wildlife that supplement mineral intake via soil and water consumption, exposing these animals to CWD prions. Exposure of predators and scavengers to CWD prions via consumption of infected tissue has been previously documented [23]; our results suggest that environmental exposure of non-cervid animal groups can also occur via environmental routes.
We also detected CWD prions in fecal samples collected in proximity to a mineral lick, indicating that fecal excretion represents a route of CWD deposition into the environment with potential transmission to susceptible cervids [19]. Deposition of fecal pellets by white-tailed deer near bait sites increases with higher deer visitation [52] and similar patterns probably occur at mineral licks. Thus, increased local fecal deposition by CWD-infected deer likely contributes to increased environmental concentrations of prions in and around mineral licks. Deer generally avoid consumption of feces [52]; however, the apparent long-term duration of prion infectivity in the environment [27–29], the enhanced disease transmission by soil-bound prions combined with the repeated visitation, long-term existence of and multi-generational use of mineral licks suggest the impact of concentrated environmental contamination on the dynamics of disease transmission warrants further investigation. Recent laboratory research indicates plants grown in prion-contaminated soil can accumulate prions [53]. Our data suggest that plants growing near contaminated mineral licks may warrant investigation as a source of prions for foraging animals. Areas where cervids congregate for mineral consumption, feeding and baiting sites, winter yarding, wallows [54] or other activities where CWD prions are deposited in the environment may also provide potential long-term reservoirs for transmission to cervid and non-cervid species.
CONCLUSIONS
We used mb-PMCA to detect CWD in soil and water from mineral licks naturally contaminated with prions and used by free-ranging deer, livestock, and non-cervid wildlife species. Detection of prions in environmental reservoirs represents an important first step in understanding the contribution of environmental transmission to CWD epizootics and potential for cross-species transmission. The present study characterized an environmental prion reservoir by (1) identifying an apparent “hot spot” of deposition and potential exposure to both cervid and non-cervid species; (2) indicating CWD prions shed by free-ranging cervids are present in areas of frequent use leading to environmental contamination and potentially plant uptake; and (3) motivating investigation of the exposure and susceptibility of non-cervid species to CWD contaminated soil, water, and plant materials. Future research should be directed at quantifying CWD prion concentrations at mineral licks and other areas where cervids congregate, determining the persistence of prion infectivity at these sites, delineating spatial-temporal patterns of environmental prion deposition and accumulation, and assessing consumption by susceptible animals. Identifying additional environmental reservoirs of CWD prions and determining the contributions of direct and indirect transmission over the course of CWD outbreaks represent key aims in advancing understanding of long-term CWD infection dynamics.
SUNDAY, DECEMBER 29, 2013
Impacts of wildlife baiting and supplemental feeding on infectious disease transmission risk: A synthesis of knowledge
Preventive Veterinary Medicine Available online 26 November 2013
Impacts of wildlife baiting and supplemental feeding on infectious disease transmission risk: A synthesis of knowledge
Anja Sorensena, Floris M. van Beesta, b, Ryan K. Brooka, Corresponding author contact information, E-mail the corresponding author
a Department of Animal and Poultry Science & Indigenous Land Management Institute, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
b Department of Bioscience, Arctic Environment, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark Abstract
Baiting and supplemental feeding of wildlife are widespread, yet highly controversial management practices, with important implications for ecosystems, livestock production, and potentially human health. An often underappreciated threat of such feeding practices is the potential to facilitate intra- and inter-specific disease transmission. We provide a comprehensive review of the scientific evidence of baiting and supplemental feeding on disease transmission risk in wildlife, with an emphasis on large herbivores in North America.
While the objectives of supplemental feeding and baiting typically differ, the effects on disease transmission of these practices are largely the same. Both feeding and baiting provide wildlife with natural or non-natural food at specific locations in the environment, which can result in large congregations of individuals and species in a small area and increased local densities.
Feeding can lead to increased potential for disease transmission either directly (via direct animal contact) or indirectly (via feed functioning as a fomite, spreading disease into the adjacent environment and to other animals).
We identified numerous diseases that currently pose a significant concern to the health of individuals and species of large wild mammals across North America, the spread of which are either clearly facilitated or most likely facilitated by the application of supplemental feeding or baiting. Wildlife diseases also have important threats to human and livestock health.
Although the risk of intra- and inter-species disease transmission likely increases when animals concentrate at feeding stations, only in a few cases was disease prevalence and transmission measured and compared between populations. Mostly these were experimental situations under controlled conditions, limiting direct scientific evidence that feeding practices exacerbates disease occurrence, exposure, transmission, and spread in the environment.
Vaccination programs utilizing baits have received variable levels of success. Although important gaps in the scientific literature exist, current information is sufficient to conclude that providing food to wildlife through supplemental feeding or baiting has great potential to negatively impact species health and represents a non-natural arena for disease transmission and preservation. Ultimately, this undermines the initial purpose of feeding practices and represents a serious risk to the maintenance of biodiversity, ecosystem functioning, human health, and livestock production. Managers should consider disease transmission as a real and serious concern in their decision to implement or eliminate feeding programs. Disease surveillance should be a crucial element within the long-term monitoring of any feeding program in combination with other available preventive measures to limit disease transmission and spread.
Keywords Artificial feeding; Baiting; Bovine tuberculosis; Chronic wasting disease; Elk; Vaccination; White-tailed deer
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There are no figures or tables for this document.
Corresponding author contact information Corresponding author at: Department of Animal and Poultry Science & Indigenous Land Management Institute, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada. Tel.: +1 306 966 4120; fax: +1 306 966 4151. Copyright © 2013 Elsevier B.V. All rights reserved.
SUNDAY, DECEMBER 29, 2013
Impacts of wildlife baiting and supplemental feeding on infectious disease transmission risk: A synthesis of knowledge
01-19-2012, 05:58 PM
Elk and Deer Use of Mineral Licks: Implications for Disease Transmission
Kurt C. VerCauteren1*, Michael J. Lavelle1, Gregory E. Phillips1, Justin W. Fischer1, and Randal S. Stahl1 1United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521-2154, USA *Cooresponding author e-mail: kurt.c.vercauteren@aphis.usda.gov
North American cervids require and actively seek out minerals to satisfy physiological requirements. Minerals required by free-ranging cervids exist within natural and artificial mineral licks that commonly serve as focal sites for cervids. Ingestion of soils contaminated with the agent that causes chronic wasting disease (CWD) may result in risk of contracting CWD. Our objective was to evaluate the extent and nature of use of mineral licks by CWD-susceptible cervid species. We used animal-activated cameras to monitor use of 18 mineral licks between 1 June and 16 October 2006 in Rocky Mountain National Park, north-central Colorado. We also assessed mineral concentrations at mineral licks to evaluate correlations between visitation rates and site-specific characteristics. We collected > 400,000 images of which 991 included elk, 293 included deer, and 6 included moose. We documented elk and deer participating in a variety of potentially risky behaviors (e.g., ingesting soil, ingesting water, defecating, urinating) while at mineral licks. Results from the mineral analyses combined with camera data revealed that visitation was highest at sodium-rich mineral licks. Mineral licks may play a role in disease transmission by acting as sites of increased interaction as well as reservoirs for deposition, accumulation, and ingestion of disease agents.
MONDAY, JANUARY 05, 2009
CWD, GAME FARMS, BAITING, AND POLITICS
THURSDAY, AUGUST 28, 2008
cwd, feeding, and baiting piles
A Risk-based Audit of the Captive/Privatelyowned Cervid Industry in Michigan Michigan Department of Natural Resources Report Series Issue Report No. 1 March 10, 2005
Areas where cervids congregate for mineral consumption, feeding and baiting sites, winter yarding, wallows [54] or other activities where CWD prions are deposited in the environment may also provide potential long-term reservoirs for transmission to cervid and non-cervid species.
Conclusions
We used mb-PMCA to detect CWD in soil and water from mineral licks naturally contaminated with prions and used by free-ranging deer, livestock, and non-cervid wildlife species. Detection of prions in environmental reservoirs represents an important first step in understanding the contribution of environmental transmission to CWD epizootics and potential for cross-species transmission. The present study characterized an environmental prion reservoir by (1) identifying an apparent “hot spot” of deposition and potential exposure to both cervid and non-cervid species; (2) indicating CWD prions shed by free-ranging cervids are present in areas of frequent use leading to environmental contamination and potentially plant uptake; and (3) motivating investigation of the exposure and susceptibility of non-cervid species to CWD contaminated soil, water, and plant materials. Future research should be directed at quantifying CWD prion concentrations at mineral licks and other areas where cervids congregate, determining the persistence of prion infectivity at these sites, delineating spatial-temporal patterns of environmental prion deposition and accumulation, and assessing consumption by susceptible animals. Identifying additional environmental reservoirs of CWD prions and determining the contributions of direct and indirect transmission over the course of CWD outbreaks represent key aims in advancing understanding of long-term CWD infection dynamics.
In summary, our results establish aerosols as a surprisingly efficient modality of prion transmission. This novel pathway of prion transmission is not only conceptually relevant for the field of prion research, but also highlights a hitherto unappreciated risk factor for laboratory personnel and personnel of the meat processing industry. In the light of these findings, it may be appropriate to revise current prion-related biosafety guidelines and health standards in diagnostic and scientific laboratories being potentially confronted with prion infected materials. While we did not investigate whether production of prion aerosols in nature suffices to cause horizontal prion transmission, the finding of prions in biological fluids such as saliva, urine and blood suggests that it may be worth testing this possibility in future studies.
ponder this; ***> Adriano Aguzzi...''We even showed that a prion AEROSOL will infect 100% of mice within 10 seconds of exposure''
SUNDAY, SEPTEMBER 1, 2019
FDA Reports on VFD Compliance
Before and after the current Veterinary Feed Directive (VFD) rules took full effect in January, 2017, the FDA focused primarily on education and outreach to help feed mills, veterinarians and producers understand and comply with the requirements. Since then, FDA has gradually increased the number of VFD inspections and initiated enforcement actions when necessary.
FRIDAY, JULY 26, 2019
Chronic Wasting Disease in Cervids: Implications for Prion Transmission to Humans and Other Animal Species
FRIDAY, JULY 26, 2019
Chronic Wasting Disease in Cervids: Implications for Prion Transmission to Humans and Other Animal Species
> However, to date, no CWD infections have been reported in people.
key word here is ‘reported’. science has shown that CWD in humans will look like sporadic CJD. SO, how can one assume that CWD has not already transmitted to humans? they can’t, and it’s as simple as that. from all recorded science to date, CWD has already transmitted to humans, and it’s being misdiagnosed as sporadic CJD. …terry
*** LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$ ***
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
snip...see more;
MONDAY, FEBRUARY 25, 2019
MAD DOGS AND ENGLISHMEN BSE, SCRAPIE, CWD, CJD, TSE PRION A REVIEW 2019
WEDNESDAY, JULY 31, 2019
The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
***> cattle, pigs, sheep, cwd, tse, prion, oh my!
***> In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006).
Sheep and cattle may be exposed to CWD via common grazing areas with affected deer but so far, appear to be poorly susceptible to mule deer CWD (Sigurdson, 2008). In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006). It is not known how susceptible humans are to CWD but given that the prion can be present in muscle, it is likely that humans have been exposed to the agent via consumption of venison (Sigurdson, 2008). Initial experimental research suggests that human susceptibility to CWD is low and there may be a robust species barrier for CWD transmission to humans (Sigurdson, 2008), however the risk appetite for a public health threat may still find this level unacceptable.
cwd scrapie pigs oral routes
***> However, at 51 months of incubation or greater, 5 animals were positive by one or more diagnostic methods. Furthermore, positive bioassay results were obtained from all inoculated groups (oral and intracranial; market weight and end of study) suggesting that swine are potential hosts for the agent of scrapie. <***
>*** 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. <***
***> Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 5="" 6="" at="" by="" detected="" eia.="" examined="" group="" in="" intracranial="" least="" lymphoid="" month="" months="" of="" one="" pigs="" positive="" prpsc="" quic="" the="" tissues="" was="">6 months group, 5/6 pigs in the oral <6 4="" and="" group="" months="" oral="">6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%).
***> Conclusions: This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge. CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period.
This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease.
Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
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.....
36% in 2007 (Almberg et al., 2011). In such areas, population declines of deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of Colorado, the prevalence can be as high as 30% (EFSA, 2011).
The clinical signs of CWD in affected adults are weight loss and behavioural changes that can span weeks or months (Williams, 2005). In addition, signs might include excessive salivation, behavioural alterations including a fixed stare and changes in interaction with other animals in the herd, and an altered stance (Williams, 2005). These signs are indistinguishable from cervids experimentally infected with bovine spongiform encephalopathy (BSE).
Given this, if CWD was to be introduced into countries with BSE such as GB, for example, infected deer populations would need to be tested to differentiate if they were infected with CWD or BSE to minimise the risk of BSE entering the human food-chain via affected venison.
snip.....
The rate of transmission of CWD has been reported to be as high as 30% and can approach 100% among captive animals in endemic areas (Safar et al., 2008).
snip.....
In summary, in endemic areas, there is a medium probability that the soil and surrounding environment is contaminated with CWD prions and in a bioavailable form. In rural areas where CWD has not been reported and deer are present, there is a greater than negligible risk the soil is contaminated with CWD prion.
snip.....
In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible... For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.
snip.....
Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.
snip.....
i urge you all to read this in full very, very, carefully. the fda mad cow feed ban never was, still ain't, all lies...terry
SUNDAY, SEPTEMBER 1, 2019
FDA Reports on VFD Compliance
Before and after the current Veterinary Feed Directive (VFD) rules took full effect in January, 2017, the FDA focused primarily on education and outreach to help feed mills, veterinarians and producers understand and comply with the requirements. Since then, FDA has gradually increased the number of VFD inspections and initiated enforcement actions when necessary.
TUESDAY, APRIL 18, 2017
*** EXTREME USA FDA PART 589 TSE PRION FEED LOOP HOLE STILL EXIST, AND PRICE OF POKER GOES UP ***
THURSDAY, AUGUST 08, 2019
Raccoons accumulate PrPSc after intracranial inoculation with the agents of chronic wasting disease (CWD) or transmissible mink encephalopathy (TME) but not atypical scrapie
SUNDAY, SEPTEMBER 08, 2019
Wisconsin Laboratory Testing Options for Prion Diseases, Wisconsin Neurologists, Clinical Laboratory Directors, and Infection Preventionists, Please Distribute Widely
Preparing for the Storm
***>like i said, your either all in, or, your just standing on the sideline whining, and your part of the problem...terry
33. Detection of CWD prions in third eyelids of deer and elk
Sarah K. Coopera, Clare E. Hoovera,b, Davin M. Hendersona, Nathaniel D. Denkersa, Candace K. Mathiasona and Edward A. Hoovera
aPrion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA; bAstraZeneca, Waltham, NJ, USA
CONTACT Sarah K. Cooper scooper2@rams.colostate.edu
ABSTRACT
Background: The increasing prevalence of CWD globally, makes critical the development of fast, cost-effective methods to detect the disease in hunter-harvested deer and assist wildlife population disease management. Based in part on the demonstration of PrPSc in the third eyelid lymphoid follicle in sheep with scrapie, we explored the third eyelid for its potential as a non-invasive and easily accessible lymphoid tissue that could be sampled without special anatomical training antemortem and postmortem for PrPCWD detection by real-time quaking induced conversion (RT-QuIC) and immunohistochemistry (IHC).
Methods: We compared RT-QuIC detection sensitivity in the third eyelid to the retropharyngeal lymph node and obex region of the brain from experimentally CWD inoculated white-tailed deer and naturally occurring subclinical elk using IHC.
We examined symptomatic and asymptomatic white-tailed deer inoculated with CWD(+) and CWD(-) brain homogenate or saliva via the per os or aerosol route.
In addition, we examined samples from asymptomatic, naturally exposed elk which were culled due to being RAMALT biopsy positive or suspect by RT-QuIC.
Results: We identified prion seeding activity in third eyelids in 24 out of 25 (96%) samples from terminal, experimentally CWD-infected deer and found RT-QuIC positivity in the third eyelid as early as 1 month after experimental exposure to CWD. In addition, we identified prion seeding activity in third eyelids in 17 out of 25 (68%) samples asymptomatic, naturally exposed elk. By contrast, IHC detected prion deposition in third eyelid lymphoid follicles in 5 of 10 deer (50%). We show that RT-QuIC can be more sensitive for CWD prion detection in the third eyelid compared to IHC.
Conclusions: RT-QuIC testing on the third eyelid is a rapid and sensitive means for post-mortem detection of CWD with potential to augment CWD diagnostics and hunter testing compliance.
Funding
Supported by NIH R01-NS-061902, P01-AI-077774, F30-ODO-118,143, T32-OD0-10,437
98. Longitudinal comparison of real-time conversion and immunohistochemistry for detection of chronic wasting disease in orally exposed white-tailed deer
Nathaniel D. Denkersa, Davin M. Hendersona, Clare E. Hoovera,b*, Amy V. Nallsa, Erin McNultya, Candace K. Mathiasona and Edward A. Hoovera
aPrion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
CONTACT Nathaniel D. Denkers nathaniel.denkers@colostate.edu
*Present address: AstraZeneca, Waltham, NJ
ABSTRACT
Background: Chronic wasting disease (CWD) continues to expand across North America and Canada, and more recently was discovered in Scandinavia. While the exact mechanism of CWD transmission has yet to be elucidated, early diagnosis of infected animals remains a priority in curtailing its spread. While immunohistochemistry (IHC) and enzyme linked immunosorbent assay (ELISA) remain the gold standards for diagnosing CWD, real-time quaking induced conversion (RT-QuIC) is capable of detecting substantially lower concentrations of prions, which may translate into detection earlier in disease course. In this study, we sought to compare the sensitivity of RT-QuIC and IHC on a series of longitudinal tonsil and recto-anal mucosal lymphoid tissue (RAMALT) biopsies from white-tailed deer during the course of CWD progression.
Methods: White-tailed deer were inoculated via the per os (PO) route with CWD(+) [n = 20] and CWD(-) [n = 4] inocula (brain homogenate or saliva) and paired tonsil and RAMALT biopsies were collected every 3 months thereafter. Biopsies were assayed for prion seeding activity by RT-QuIC and for PrPCWD deposition by IHC.
Results: RT-QuIC detected seeding activity in 10 of 20 (50%) tonsil biopsies prior to IHC detection, on average of 5.1 months (3–15 months) earlier. In RAMALT biopsies, detectable seeding activity was observed in 13 of 20 (65%) samples prior to IHC detection, on average 4.6 months (3–15 months) earlier. In the remaining biopsies, detection was concurrent by both methods. At no sampling point did a positive IHC result precede a positive RT-QuIC result. Of note, for biopsy samples that had already been determined positive by both RT-QuIC and IHC in a previous collection, RT-QuIC detected seeding activity in seven (7) tonsil and four (4) RAMALT follow-up biopsies even though no lymphoid follicles were present in the paired samples to assess positivity by IHC. All biopsies from CWD(-) deer were negative by both assays throughout the study. Overall, these results demonstrate that RT-QuIC detected CWD positivity in both tonsil and RAMALT biopsies approximately 5 months prior to IHC. Moreover, seeding activity was detectable even when (due to poor biopsy sampling) lymphoid follicles were not present to permit meaningful IHC analysis.
Conclusions: These data indicate that RT-QuIC is more sensitive than IHC in detecting CWD infection, and could thereby be useful in determining future management strategies.
Funding
Supported by NIH R01-NS-061902, P01-AI-077774, F30-ODO-118,143, T32-OD0-10,437
124. Longitudinal studies of CWD after low-dose oral exposure in white-tailed deer
Clare E. Hoover*, Nathaniel D. Denkers, Kristen A. Davenport, Davin M. Henderson, Amy V. Nalls, Erin McNulty, Joanne Tennant, Sarah Cooper, Manci Li, Lauren Bracchi, Candace K. Mathiason and Edward A. Hoover
Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
CONTACT Edward A. Hoover edward.hoover@colostate.edu
*Present address: AstraZeneca, Waltham, NJ
ABSTRACT
Background: The facile transmission of chronic wasting disease (CWD) in North America, Asia and Europe continues despite exposure to very low concentrations of prions shed by infected cervids in secreta and excreta. Explanations for this enigma could be that excreted prions may have enhanced infectivity and/or that the infectious prion dose is just quite low. Historical studies exploring CWD pathogenesis in deer have used exposures to CWD-positive brain homogenates containing from 0.5 to 10 g of brain – doses much higher than those measured in excreta, and thereby likely to ever occur in nature. We thereby sought to more closely emulate natural exposure context in our current experimental studies.
Methods: To explore how the origin or infectious dose of CWD prions may influence disease transmission or pathogenesis, we orally exposed cohorts of n = 4/group white-tailed deer to low doses of CWD presented as either CWD-positive brain homogenate (containing either 1 mg or 300 ng of brain) or to an amount of pooled saliva from CWD+ donors and containing prion seeding activity (by RT-QuIC) equivalent to 300 ng of CWD+ brain [1]. Inoculated deer were then longitudinally monitored for: (a) onset of prion infection in biopsied tonsil and recto-anal lymphoid tissues by RT-QuIC and immunohistochemistry; (b) prion shedding in saliva and faeces (by RT-QuIC); (c) onset of clinical signs (weekly observation and scoring); and (d) time to clinical disease.
Results: We first detected CWD infection by RT-QuIC seeding activity in tonsil biopsies at 6 or 9 months post exposure, in all inoculation cohorts. Prion shedding in saliva was detected (by RT-QuIC or PMCA-RT-QuIC [2]) concurrent with the first positive tonsil biopsy. Detection of prion seeding activity in faeces was less common overall and its onset observed after positivity in recto-anal lymphoid tissue biopsies. In comparison to historical studies, in which >1,000-fold higher inoculation doses were used, the time to first detection on infection (by tonsil biopsy) was prolonged by ~6 months. However, among the low-dose inoculation cohorts in this study, neither the attack rate, prion shedding profile, nor long-term disease course differed significantly, including the deer exposed to prions of saliva vs. brain origin.
Conclusions: These studies demonstrate that (a) much lower doses of CWD prions that have been used historically for point source exposure studies are sufficient to induce prion infection, shedding, and disease; and (b) although time to first detectable positivity is lengthened, the qualitative aspects of disease pathogenesis thereafter are indistinguishable by inoculum source or exposure magnitude.
Our future studies will aim at establishing the minimum oral infectious dose for CWD in deer and on exploring exposure cofactors.
Supported by NIH R01-NS-061902, P01-AI-077774, F30-ODO-118,143, T32-OD0-10,437
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
ABSTRACT
Introduction: Transmissible spongiform encephalopathy (TSE) is a fatal neurodegenerative disorder, which is so-called as prion diseases due to the causative agents (PrPSc). TSEs are believed to be due to the template-directed accumulation of disease-associated prion protein, generally designated PrPSc. Chronic wasting disease (CWD) is the prion disease that is known spread horizontally. CWD has confirmed last in Republic of Korea in 2016 since first outbreak of CWD in 2001. The environmental reservoirs mediate the transmission of this disease. The significant levels of infectivity have been detected in the saliva, urine, and faeces of TSE-infected animals. Soil can serve as a stable reservoir for infectious prion proteins. We found that PrPCWD can be extracted and detected in CWD contaminated soil which has kept at room temperature until 4 years after 0.001 ~ 1% CWD exposure and natural CWD-affected farm soil through PBS washing and sPMCAb.
Materials and Methods: Procedure of serial PMCAb. CWD contaminated soil which has kept at room temperature (RT) for 1 ~ 4 year after 0.001%~1% CWD brain homogenates exposure for 4 months collected 0.14 g. The soil was collected by the same method once of year until 4 year after stop CWD exposure. We had conducted the two steps. There are two kinds of 10 times washing step and one amplification step. The washing step was detached PrPSc from contaminated soil by strong vortex with maximum rpm. We harvest supernatant every time by 10 times. As the other washing step, the Washed soil was made by washing 10 times soil using slow rotator and then harvest resuspended PBS for removing large impurity material. Last step was prion amplification step for detection of PrPCWD in soil supernatant and the washed soil by sPMCAb. Normal brain homogenate (NBH) was prepared by homogenization of brains with glass dounce in 9 volumes of cold PBS with TritonX-100, 5 mM EDTA, 150 mM NaCl and 0.05% Digitonin (sigma) plus Complete mini protease inhibitors (Roche) to a final concentration of 5%(w/v) NBHs were centrifuged at 2000 g for 1 min, and supernatant removed and frozen at −70 C for use. CWD consisted of brain from natural case in Korea and was prepared as 10%(w/v) homogenate. Positive sample was diluted to a final dilution 1:1000 in NBH, with serial 3:7 dilutions in NBH. Sonication was performed with a Misonix 4000 sonicator with amplitude set to level 70, generating an average output of 160W with two teflon beads during each cycle. One round consisted of 56 cycles of 30 s of sonication followed 9 min 30 s of 37°C incubation. Western Blotting (WB) for PrPSc detection. The samples (20 µL) after each round of amplification were mixed with proteinase K (2 mg/ml) and incubated 37°C for 1 h. Samples were separated by SDS-PAGE and transferred onto PVDF membrane. After blocking, the membrane was incubated for 1 h with 1st antibody S1 anti rabbit serum (APQA, 1:3000) and developed with enhanced chemiluminescence detection system.
Results: We excluded from first to third supernatant in view of sample contamination. It was confirmed abnormal PrP amplification in all soil supernatants from fourth to tenth. From 0.01% to 1% contaminated washed soils were identified as abnormal prions. 0.001% contaminated washed soil did not show PrP specific band (Fig 1). The soil was collected by the same method once of year until 4 year after stop CWD exposure. After sPMCAb, there were no PrPCWD band in from second to fourth year 0.001% washed soil. but It was confirmed that the abnormal prion was amplified in the washing supernatant which was not amplified in the washed soil. we have decided to use soil supernatant for soil testing (Fig. 2). After third rounds of amplification, PrPSc signals observed in three out of four sites from CWD positive farm playground. No signals were observed in all soil samples from four CWD negative farm (Fig. 3).
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.
===
186. Serial detection of hematogenous prions in CWD-infected deer
Amy V. Nalls, Erin E. McNulty, Nathaniel D. Denkers, Edward A. Hoover and Candace K. Mathiason
Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
CONTACT Amy V. Nalls amy.nalls@colostate.edu
ABSTRACT
Blood contains the infectious agent associated with prion disease affecting several mammalian species, including humans, cervids, sheep, and cattle. It has been confirmed that sufficient prion agent is present in the blood of both symptomatic and asymptomatic carriers to initiate the amyloid templating and accumulation process that results in this fatal neurodegenerative disease. Yet, to date, the ability to detect blood-borne prions by in vitro methods remains difficult.
We have capitalized on blood samples collected from longitudinal chronic wasting disease (CWD) studies in the native white-tailed deer host to examine hematogenous prion load in blood collected minutes, days, weeks and months post exposure. Our work has focused on refinement of the amplification methods RT-QuIC and PMCA. We demonstrate enhanced in vitro detection of amyloid seeding activity (prions) in blood cell fractions harvested from deer orally-exposed to 300 ng CWD positive brain or saliva.
These findings permit assessment of the role hematogenous prions play in the pathogenesis of CWD and provide tools to assess the same for prion diseases of other mammalian species.
Considering the oral secretion of prions, saliva from CWD-infected deer was shown to transmit disease to other susceptible naïve deer when harvested from the animals in both the
and preclinical stages69
of infection, albeit within relatively large volumes of saliva (50 ml). In sheep with preclinical, natural scrapie infections, sPMCA facilitated the detection of PrPSc within buccal swabs throughout most of the incubation period of the disease with an apparent peak in prion secretion around the mid-term of disease progression.70
The amounts of prion present in saliva are likely to be low as indicated by CWD-infected saliva producing prolonged incubation periods and incomplete attack rates within the transgenic mouse bioassay.41
snip...
Indeed, it has also been shown that the scrapie and CWD prions are excreted in urine, feces and saliva and are likely to be excreted from skin. While levels of prion within these excreta/secreta are very low, they are produced throughout long periods of preclinical disease as well as clinical disease. Furthermore, the levels of prion in such materials are likely to be increased by concurrent inflammatory conditions affecting the relevant secretory organ or site. Such dissemination of prion into the environment is very likely to facilitate the repeat exposure of flockmates to low levels of the disease agent, possibly over years.
snip...
Given the results with scrapie-contaminated milk and CWD-contaminated saliva, it seems very likely that these low levels of prion in different secreta/excreta are capable of transmitting disease upon prolonged exposure, either through direct animal-to-animal contact or through environmental reservoirs of infectivity.
the other part, these tissues and things in the body then shed or secrete prions which then are the route to other animals into the environment, so in particular, the things, the secretions that are infectious are salvia, feces, blood and urine. so pretty much anything that comes out of a deer is going to be infectious and potential for transmitting disease.
***>>> Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
========================
Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
HUNTERS, CWD TSE PRION, THIS SHOULD A WAKE UP CALL TO ALL OF YOU GUTTING AND BONING OUT YOUR KILL IN THE FIELD, AND YOUR TOOLS YOU USE...
* 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]
Wednesday, September 11, 2019
Is the re-use of sterilized implant abutments safe enough? (Implant abutment safety) iatrogenic TSE Prion
SATURDAY, MARCH 16, 2019
Medical Devices Containing Materials Derived from Animal Sources (Except for In Vitro Diagnostic Devices) Guidance for Industry and Food and Drug Administration Staff Document issued on March 15, 2019 Singeltary Submission
2018 - 2019
***> This is very likely to have parallels with control efforts for CWD in cervids.
Rapid recontamination of a farm building occurs after attempted prion removal
Kevin Christopher Gough, BSc (Hons), PhD1, Claire Alison Baker, BSc (Hons)2, Steve Hawkins, MIBiol3, Hugh Simmons, BVSc, MRCVS, MBA, MA3, Timm Konold, DrMedVet, PhD, MRCVS3 and Ben Charles Maddison, BSc (Hons), PhD2
Abstract
The transmissible spongiform encephalopathy scrapie of sheep/goats and chronic wasting disease of cervids are associated with environmental reservoirs of infectivity.
Preventing environmental prions acting as a source of infectivity to healthy animals is of major concern to farms that have had outbreaks of scrapie and also to the health management of wild and farmed cervids.
Here, an efficient scrapie decontamination protocol was applied to a farm with high levels of environmental contamination with the scrapie agent.
Post-decontamination, no prion material was detected within samples taken from the farm buildings as determined using a sensitive in vitro replication assay (sPMCA).
A bioassay consisting of 25 newborn lambs of highly susceptible prion protein genotype VRQ/VRQ introduced into this decontaminated barn was carried out in addition to sampling and analysis of dust samples that were collected during the bioassay.
Twenty-four of the animals examined by immunohistochemical analysis of lymphatic tissues were scrapie-positive during the bioassay, samples of dust collected within the barn were positive by month 3.
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.
snip...
As in the authors' previous study,12 the decontamination of this sheep barn was not effective at removing scrapie infectivity, and despite the extra measures brought into this study (more effective chemical treatment and removal of sources of dust) the overall rates of disease transmission mirror previous results on this farm. With such apparently effective decontamination (assuming that at least some sPMCA seeding ability is coincident with infectivity), how was infectivity able to persist within the environment and where does infectivity reside? Dust samples were collected in both the bioassay barn and also a barn subject to the same decontamination regime within the same farm (but remaining unoccupied). Within both of these barns dust had accumulated for three months that was able to seed sPMCA, indicating the accumulation of scrapie-containing material that was independent of the presence of sheep that may have been incubating and possibly shedding low amounts of infectivity.
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.
Acknowledgements The authors thank the APHA farm staff, Tony Duarte, Olly Roberts and Margaret Newlands for preparation of the sheep pens and animal husbandry during the study. The authors also thank the APHA pathology team for RAMALT and postmortem examination.
Funding This study was funded by DEFRA within project SE1865.
Competing interests None declared.
Saturday, January 5, 2019
Rapid recontamination of a farm building occurs after attempted prion removal
THURSDAY, FEBRUARY 28, 2019
BSE infectivity survives burial for five years with only limited spread
***> CONGRESSIONAL ABSTRACTS PRION CONFERENCE 2018
P69 Experimental transmission of CWD from white-tailed deer to co-housed reindeer
Mitchell G (1), Walther I (1), Staskevicius A (1), Soutyrine A (1), Balachandran A (1)
(1) National & OIE Reference Laboratory for Scrapie and CWD, Canadian Food Inspection Agency, Ottawa, Ontario, Canada.
Chronic wasting disease (CWD) continues to be detected in wild and farmed cervid populations of North America, affecting predominantly white-tailed deer, mule deer and elk. Extensive herds of wild caribou exist in northern regions of Canada, although surveillance has not detected the presence of CWD in this population. Oral experimental transmission has demonstrated that reindeer, a species closely related to caribou, are susceptible to CWD. Recently, CWD was detected for the first time in Europe, in wild Norwegian reindeer, advancing the possibility that caribou in North America could also become infected. Given the potential overlap in habitat between wild CWD-infected cervids and wild caribou herds in Canada, we sought to investigate the horizontal transmissibility of CWD from white-tailed deer to reindeer.
Two white-tailed deer were orally inoculated with a brain homogenate prepared from a farmed Canadian white-tailed deer previously diagnosed with CWD. Two reindeer, with no history of exposure to CWD, were housed in the same enclosure as the white-tailed deer, 3.5 months after the deer were orally inoculated. The white-tailed deer developed clinical signs consistent with CWD beginning at 15.2 and 21 months post-inoculation (mpi), and were euthanized at 18.7 and 23.1 mpi, respectively. Confirmatory testing by immunohistochemistry (IHC) and western blot demonstrated widespread aggregates of pathological prion protein (PrPCWD) in the central nervous system and lymphoid tissues of both inoculated white-tailed deer. Both reindeer were subjected to recto-anal mucosal associated lymphoid tissue (RAMALT) biopsy at 20 months post-exposure (mpe) to the white-tailed deer. The biopsy from one reindeer contained PrPCWD confirmed by IHC. This reindeer displayed only subtle clinical evidence of disease prior to a rapid decline in condition requiring euthanasia at 22.5 mpe. Analysis of tissues from this reindeer by IHC revealed widespread PrPCWD deposition, predominantly in central nervous system and lymphoreticular tissues. Western blot molecular profiles were similar between both orally inoculated white-tailed deer and the CWD positive reindeer. Despite sharing the same enclosure, the other reindeer was RAMALT negative at 20 mpe, and PrPCWD was not detected in brainstem and lymphoid tissues following necropsy at 35 mpe. Sequencing of the prion protein gene from both reindeer revealed differences at several codons, which may have influenced susceptibility to infection.
Natural transmission of CWD occurs relatively efficiently amongst cervids, supporting the expanding geographic distribution of disease and the potential for transmission to previously naive populations. The efficient horizontal transmission of CWD from white-tailed deer to reindeer observed here highlights the potential for reindeer to become infected if exposed to other cervids or environments infected with CWD.
***> 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.
Gudmundur Georgsson,1 Sigurdur Sigurdarson2 and Paul Brown3
Correspondence
Gudmundur Georgsson ggeorgs@hi.is
1 Institute for Experimental Pathology, University of Iceland, Keldur v/vesturlandsveg, IS-112 Reykjavı´k, Iceland
2 Laboratory of the Chief Veterinary Officer, Keldur, Iceland
3 Bethesda, Maryland, USA
Received 7 March 2006 Accepted 6 August 2006
In 1978, a rigorous programme was implemented to stop the spread of, and subsequently eradicate, sheep scrapie in Iceland. Affected flocks were culled, premises were disinfected and, after 2–3 years, restocked with lambs from scrapie-free areas. Between 1978 and 2004, scrapie recurred on 33 farms. 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. Of special interest was one farm with a small, completely self-contained flock where scrapie recurred 18 years after culling, 2 years after some lambs had been housed in an old sheephouse that had never been disinfected. Epidemiological investigation established with near certitude that the disease had not been introduced from the outside and it is concluded that the agent may have persisted in the old sheep-house for at least 16 years.
TITLE: PATHOLOGICAL FEATURES OF CHRONIC WASTING DISEASE IN REINDEER AND DEMONSTRATION OF HORIZONTAL TRANSMISSION
*** DECEMBER 2016 CDC EMERGING INFECTIOUS DISEASE JOURNAL CWD HORIZONTAL TRANSMISSION
SEE;
Back around 2000, 2001, or so, I was corresponding with officials abroad during the bse inquiry, passing info back and forth, and some officials from here inside USDA aphis FSIS et al. In fact helped me get into the USA 50 state emergency BSE conference call way back. That one was a doozy. But I always remember what “deep throat” I never knew who they were, but I never forgot;
Some unofficial information from a source on the inside looking out -
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
Infectivity surviving ashing to 600*C is (in my opinion) degradable but infective. based on Bown & Gajdusek, (1991), landfill and burial may be assumed to have a reduction factor of 98% (i.e. a factor of 50) over 3 years. CJD-infected brain-tissue remained infectious after storing at room-temperature for 22 months (Tateishi et al, 1988). Scrapie agent is known to remain viable after at least 30 months of desiccation (Wilson et al, 1950). and pastures that had been grazed by scrapie-infected sheep still appeared to be contaminated with scrapie agent three years after they were last occupied by sheep (Palsson, 1979).
Dr. Paul Brown Scrapie Soil Test BSE Inquiry Document
Using in vitro Prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.
Claudio Soto Mitchell Center for Alzheimer's diseases and related Brain disorders, Department of Neurology, University of Texas Medical School at Houston.
Prion and prion-like proteins are misfolded protein aggregates with the ability to selfpropagate to spread disease between cells, organs and in some cases across individuals. I n T r a n s m i s s i b l e s p o n g i f o r m encephalopathies (TSEs), prions are mostly composed by a misfolded form of the prion protein (PrPSc), which propagates by transmitting its misfolding to the normal prion protein (PrPC). The availability of a procedure to replicate prions in the laboratory may be important to study the mechanism of prion and prion-like spreading and to develop high sensitive detection of small quantities of misfolded proteins in biological fluids, tissues and environmental samples. Protein Misfolding Cyclic Amplification (PMCA) is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA is a platform technology that may enable amplification of any prion-like misfolded protein aggregating through a seeding/nucleation process. In TSEs, PMCA is able to detect the equivalent of one single molecule of infectious PrPSc and propagate prions that maintain high infectivity, strain properties and species specificity. Using PMCA we have been able to detect PrPSc in blood and urine of experimentally infected animals and humans affected by vCJD with high sensitivity and specificity. Recently, we have expanded the principles of PMCA to amplify amyloid-beta (Aβ) and alphasynuclein (α-syn) aggregates implicated in Alzheimer's and Parkinson's diseases, respectively. Experiments are ongoing to study the utility of this technology to detect Aβ and α-syn aggregates in samples of CSF and blood from patients affected by these diseases.
=========================
***>>> Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
========================
Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production
Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing
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
PPo4-4:
Survival and Limited Spread of TSE Infectivity after Burial
Discussion Classical scrapie is an environmentally transmissible disease because it has been reported in naïve, supposedly previously unexposed sheep placed in pastures formerly occupied by scrapie-infected sheep (4, 19, 20).
Although the vector for disease transmission is not known, soil is likely to be an important reservoir for prions (2) where – based on studies in rodents – prions can adhere to minerals as a biologically active form (21) and remain infectious for more than 2 years (22).
Similarly, chronic wasting disease (CWD) has re-occurred in mule deer housed in paddocks used by infected deer 2 years earlier, which was assumed to be through foraging and soil consumption (23).
Our study suggested that the risk of acquiring scrapie infection was greater through exposure to contaminated wooden, plastic, and metal surfaces via water or food troughs, fencing, and hurdles than through grazing.
Drinking from a water trough used by the scrapie flock was sufficient to cause infection in sheep in a clean building.
Exposure to fences and other objects used for rubbing also led to infection, which supported the hypothesis that skin may be a vector for disease transmission (9).
The risk of these objects to cause infection was further demonstrated when 87% of 23 sheep presented with PrPSc in lymphoid tissue after grazing on one of the paddocks, which contained metal hurdles, a metal lamb creep and a water trough in contact with the scrapie flock up to 8 weeks earlier, whereas no infection had been demonstrated previously in sheep grazing on this paddock, when equipped with new fencing and field furniture.
When the contaminated furniture and fencing were removed, the infection rate dropped significantly to 8% of 12 sheep, with soil of the paddock as the most likely source of infection caused by shedding of prions from the scrapie-infected sheep in this paddock up to a week earlier.
This study also indicated that the level of contamination of field furniture sufficient to cause infection was dependent on two factors: stage of incubation period and time of last use by scrapie-infected sheep.
Drinking from a water trough that had been used by scrapie sheep in the predominantly pre-clinical phase did not appear to cause infection, whereas infection was shown in sheep drinking from the water trough used by scrapie sheep in the later stage of the disease.
It is possible that contamination occurred through shedding of prions in saliva, which may have contaminated the surface of the water trough and subsequently the water when it was refilled.
Contamination appeared to be sufficient to cause infection only if the trough was in contact with sheep that included clinical cases.
Indeed, there is an increased risk of bodily fluid infectivity with disease progression in scrapie (24) and CWD (25) based on PrPSc detection by sPMCA.
Although ultraviolet light and heat under natural conditions do not inactivate prions (26), furniture in contact with the scrapie flock, which was assumed to be sufficiently contaminated to cause infection, did not act as vector for disease if not used for 18 months, which suggest that the weathering process alone was sufficient to inactivate prions.
PrPSc detection by sPMCA is increasingly used as a surrogate for infectivity measurements by bioassay in sheep or mice.
In this reported study, however, the levels of PrPSc present in the environment were below the limit of detection of the sPMCA method, yet were still sufficient to cause infection of in-contact animals.
In the present study, the outdoor objects were removed from the infected flock 8 weeks prior to sampling and were positive by sPMCA at very low levels (2 out of 37 reactions).
As this sPMCA assay also yielded 2 positive reactions out of 139 in samples from the scrapie-free farm, the sPMCA assay could not detect PrPSc on any of the objects above the background of the assay.
False positive reactions with sPMCA at a low frequency associated with de novo formation of infectious prions have been reported (27, 28).
This is in contrast to our previous study where we demonstrated that outdoor objects that had been in contact with the scrapie-infected flock up to 20 days prior to sampling harbored PrPSc that was detectable by sPMCA analysis [4 out of 15 reactions (12)] and was significantly more positive by the assay compared to analogous samples from the scrapie-free farm.
This discrepancy could be due to the use of a different sPMCA substrate between the studies that may alter the efficiency of amplification of the environmental PrPSc.
In addition, the present study had a longer timeframe between the objects being in contact with the infected flock and sampling, which may affect the levels of extractable PrPSc.
Alternatively, there may be potentially patchy contamination of this furniture with PrPSc, which may have been missed by swabbing.
The failure of sPMCA to detect CWD-associated PrP in saliva from clinically affected deer despite confirmation of infectivity in saliva-inoculated transgenic mice was associated with as yet unidentified inhibitors in saliva (29), and it is possible that the sensitivity of sPMCA is affected by other substances in the tested material.
In addition, sampling of amplifiable PrPSc and subsequent detection by sPMCA may be more difficult from furniture exposed to weather, which is supported by the observation that PrPSc was detected by sPMCA more frequently in indoor than outdoor furniture (12).
A recent experimental study has demonstrated that repeated cycles of drying and wetting of prion-contaminated soil, equivalent to what is expected under natural weathering conditions, could reduce PMCA amplification efficiency and extend the incubation period in hamsters inoculated with soil samples (30).
This seems to apply also to this study even though the reduction in infectivity was more dramatic in the sPMCA assays than in the sheep model.
Sheep were not kept until clinical end-point, which would have enabled us to compare incubation periods, but the lack of infection in sheep exposed to furniture that had not been in contact with scrapie sheep for a longer time period supports the hypothesis that prion degradation and subsequent loss of infectivity occurs even under natural conditions.
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.
These results suggest that the VRQ/VRQ sheep model may be more sensitive than sPMCA for the detection of environmentally associated scrapie, and suggest that extremely low levels of scrapie contamination are able to cause infection in susceptible sheep genotypes.
Keywords: classical scrapie, prion, transmissible spongiform encephalopathy, sheep, field furniture, reservoir, serial protein misfolding cyclic amplification
Wednesday, December 16, 2015
*** Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission ***
WEDNESDAY, MARCH 13, 2019
CWD, TSE, PRION, MATERNAL mother to offspring, testes, epididymis, seminal fluid, and blood
WEDNESDAY, JULY 31, 2019
The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
TUESDAY, SEPTEMBER 17, 2019
***> Michigan House Bill 4687 State Legislators Turn To Draft Dodger Ted Nugent To Make Scientific Decisions over DNR on CWD TSE Prion
SUNDAY, SEPTEMBER 22, 2019
***> Michigan TWO MORE CWD TSE PRION POSITIVES Total Now At 124 Positive
THURSDAY, SEPTEMBER 26, 2019
USDA Scientific Integrity Policy Departmental Regulation 1074-001 Breached
THURSDAY, OCTOBER 03, 2019
ALABAMA PREPARES FOR THE STORM Fall 2019 CWD TSE PRION Public Information Meeting Schedule
THURSDAY, OCTOBER 03, 2019
Wyoming CWD TSE Prion found in deer west of Continental Divide
THURSDAY, OCTOBER 03, 2019
Montana Huntley deer tests positive for CWD; new management zone set
THURSDAY, OCTOBER 03, 2019
Tennessee Madison County deer sampled within 10 miles of Crockett and Gibson counties has tested positive for CWD, Declared High Risk
SATURDAY, SEPTEMBER 28, 2019
Texas CWD TSE Prion aka Mad Deer Disease Detected Free Range Mule Deer El Paso 145 Positive To Date
THURSDAY, SEPTEMBER 05, 2019
Unique Profile of The Texas CWD TSE Prion isolates, the TSE Prion CWD, Scrapie, BSE in Livestock, and CJD in Humans
SUNDAY, SEPTEMBER 22, 2019
Michigan TWO MORE CWD TSE PRION POSITIVES Total Now At 124 Positive
TUESDAY, SEPTEMBER 17, 2019
Michigan House Bill 4687 State Legislators Turn To Draft Dodger Ted Nugent To Make Scientific Decisions over DNR on CWD TSE Prion
FRIDAY, SEPTEMBER 06, 2019
Montana Seventh White-tailed Deer Suspected Positive for CWD in Libby Area
MONDAY, JULY 29, 2019
Wisconsin State wildlife representatives agree on top-level priorities for controlling chronic wasting disease cwd tse prion after 3 decades of floundering
SUNDAY, SEPTEMBER 08, 2019
Wisconsin Laboratory Testing Options for Prion Diseases, Wisconsin Neurologists, Clinical Laboratory Directors, and Infection Preventionists, Please Distribute Widely
Preparing for the Storm
MONDAY, SEPTEMBER 16, 2019
CFIA 2019 National Standards for the Chronic Wasting Disease Herd Certification Programs
TUESDAY, OCTOBER 01, 2019
Genetic susceptibility to chronic wasting disease cwd tse prion?
i am concerned with the fact, the longer you can delay death with cwd, you risk having a cwd tse prion infected deer live longer in the wild or captive, thus giving more time to spread disease. you also risk developing a super cwd tse strain imo. we already have multiple strains, with what seems to be a super strain of cwd in Texas. also, with scrapie, they thought arr was resistant in sheep, until it was not...
THURSDAY, AUGUST 29, 2019
Detection of CWD in cervids by RT-QuIC assay of third eyelids
THURSDAY, AUGUST 08, 2019
Raccoons accumulate PrPSc after intracranial inoculation with the agents of chronic wasting disease (CWD) or transmissible mink encephalopathy (TME) but not atypical scrapie
FRIDAY, JULY 26, 2019
Chronic Wasting Disease in Cervids: Implications for Prion Transmission to Humans and Other Animal Species
MONDAY, FEBRUARY 25, 2019
MAD DOGS AND ENGLISHMEN BSE, SCRAPIE, CWD, CJD, TSE PRION A REVIEW 2019
WEDNESDAY, JULY 31, 2019
The agent of transmissible mink encephalopathy passaged in sheep is similar to BSE-L
THURSDAY, OCTOBER 25, 2018
Norway New additional requirements for imports of hay and straw for animal feed from countries outside the EEA due to CWD TSE Prion
Grass plants bind, retain, uptake and transport infectious prions
Sandra Pritzkow, Rodrigo Morales, [...], and Claudio Soto
Associated Data
Abstract
Prions are the protein-based infectious agents responsible for prion diseases. Environmental prion contamination has been implicated in disease transmission. Here we analyzed the binding and retention of infectious prion protein (PrPSc) to plants. Small quantities of PrPSc contained in diluted brain homogenate or in excretory materials (urine and feces) can bind to wheat grass roots and leaves. Wild type hamsters were efficiently infected by ingestion of prion-contaminated plants. The prion-plant interaction occurs with prions from diverse origins, including chronic wasting disease. Furthermore, leaves contaminated by spraying with a prion-containing preparation retained PrPSc for several weeks in the living plant. Finally, plants can uptake prions from contaminated soil and transport them to aerial parts of the plant (stem and leaves). These findings demonstrate that plants can efficiently bind infectious prions and act as carriers of infectivity, suggesting a possible role of environmental prion contamination in the horizontal transmission of the disease.
***>>> Recently, we have been using PMCA to study the role of environmental prion contamination on the horizontal spreading of TSEs. These experiments have focused on the study of the interaction of prions with plants and environmentally relevant surfaces. Our results show that plants (both leaves and roots) bind tightly to prions present in brain extracts and excreta (urine and feces) and retain even small quantities of PrPSc for long periods of time. Strikingly, ingestion of prioncontaminated leaves and roots produced disease with a 100% attack rate and an incubation period not substantially longer than feeding animals directly with scrapie brain homogenate. Furthermore, plants can uptake prions from contaminated soil and transport them to different parts of the plant tissue (stem and leaves). Similarly, prions bind tightly to a variety of environmentally relevant surfaces, including stones, wood, metals, plastic, glass, cement, etc. Prion contaminated surfaces efficiently transmit prion disease when these materials were directly injected into the brain of animals and strikingly when the contaminated surfaces were just placed in the animal cage. These findings demonstrate that environmental materials can efficiently bind infectious prions and act as carriers of infectivity, suggesting that they may play an important role in the horizontal transmission of the disease.
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Since its invention 13 years ago, PMCA has helped to answer fundamental questions of prion propagation and has broad applications in research areas including the food industry, blood bank safety and human and veterinary disease diagnosis.
TUESDAY, JULY 30, 2019
Guidelines for reporting surveillance data on Transmissible Spongiform Encephalopathies (TSE) in the EU within the framework of Regulation (EC) No 999/2001 APPROVED: 9 July 2019
THURSDAY, AUGUST 01, 2019
Europe Chronic Wasting Disease CWD TSE Prion Update August 2019
THURSDAY, SEPTEMBER 26, 2019
Sweden The third case of CWD in moose in Arjeplog is now established
SATURDAY, OCTOBER 05, 2019
Michigan MSU SCIENTISTS ARE TESTING A FASTER WAY TO DETECT CHRONIC WASTING DISEASE
FRIDAY, OCTOBER 04, 2019
Indiana CWD TSE Prion Surveillance 2019 and before?
i am not sure where you can buy weapons grade strength sodium hypochlorite, but maybe some good news, or not, i am not sure?
“Investigators note that bleach fails to penetrate tissues and should be used only as a surface decontaminant.”
FRIDAY, OCTOBER 04, 2019
Inactivation of chronic wasting disease prions using sodium hypochlorite
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. at
12:13 PM
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