Saturday, September 12, 2015
In utero transmission and tissue distribution of chronic wasting disease-associated prions in free-ranging Rocky Mountain elk
Authors: Anca Selariu1, Jenny G Powers2, Amy Nalls3, Monica Brandhuber4, Amber Mayfield5, Stephanie Fullaway6, Christy A Wyckoff7, Wilfred Goldmann8, Mark M Zabel9, Margaret A Wild10, Edward A Hoover11, Candace K Mathiason12 VIEW AFFILIATIONS
Published Ahead of Print: 09 September, 2015 Journal of General Virology doi: 10.1099/jgv.0.000281 Published Online: 09/09/2015
The presence of disease-associated prions in tissues and bodily fluids of chronic wasting disease (CWD)-infected cervids has received much investigation, yet little is known about mother to offspring transmission of CWD. Our previous work demonstrated that mother to offspring transmission is efficient in an experimental setting. To address the question of relevance in a naturally-exposed free-ranging population, we have assessed maternal and fetal tissues derived from 19 elk dam-calf pairs collected from free-ranging Rocky Mountain elk from North central Colorado, a known CWD endemic region. Conventional immunohistochemistry (IHC) identified 3/19 CWD positive dams, whereas a more sensitive assay - the serial protein misfolding cyclic amplification (sPMCA) - detected CWD prion seeding activity (PrPCWD) in 15/19 dams. PrPCWD distribution in tissues was widespread and included the central nervous system (CNS), lymphoreticular system (LRS), reproductive, secretory, excretory and adipose tissues. Interestingly, five of fifteen sPMCA positive dams showed no evidence of PrPCWD in either CNS or LRS, sites typically assessed in diagnosing CWD. Analysis of fetal tissues harvested from the fifteen sPMCA positive dams revealed PrPCWD in 80% of fetuses (12/15), regardless of gestational stage. These findings demonstrate that PrPCWD is more abundant in peripheral tissues of CWD exposed elk than current diagnostic methods suggest, and that transmission of prions from mother to offspring may contribute to the efficient transmission of the CWD in naturally exposed cervid populations.
>>>Interestingly, five of fifteen sPMCA positive dams showed no evidence of PrPCWD in either CNS or LRS, sites typically assessed in diagnosing CWD. Analysis of fetal tissues harvested from the fifteen sPMCA positive dams revealed PrPCWD in 80% of fetuses (12/15), regardless of gestational stage. These findings demonstrate that PrPCWD is more abundant in peripheral tissues of CWD exposed elk than current diagnostic methods suggest, and that transmission of prions from mother to offspring may contribute to the efficient transmission of the CWD in naturally exposed cervid populations.<<<
Thursday, May 02, 2013
*** Chronic Wasting Disease (CWD) Texas Important Update on OBEX ONLY TESTING
Wednesday, July 15, 2015
*** Additional BSE TSE prion testing detects pathologic lesion in unusual brain location and PrPsc by PMCA only, how many cases have we missed?
Journal of Wildlife Diseases, 51(4), 2015, pp. 000–000 # Wildlife Disease Association 2015
AGE AND REPEATED BIOPSY INFLUENCE ANTEMORTEM PRPCWD TESTING IN MULE DEER (ODOCOILEUS HEMIONUS) IN COLORADO, USA
Chris Geremia,1,6,7 Jennifer A. Hoeting,2 Lisa L. Wolfe,3 Nathan L. Galloway,4 Michael F. Antolin,4 Terry R. Spraker,5 Michael W. Miller,3 and N. Thompson Hobbs1 1 Natural Resource Ecology Laboratory, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523-1499, USA 2 Department of Statistics, Colorado State University, Fort Collins, Colorado 80523, USA 3 Colorado Division of Parks and Wildlife, Wildlife Health Program, 4330 Laporte Avenue, Fort Collins, Colorado 80521, USA 4 Department of Biology, Colorado State University, Fort Collins, Colorado 80523-1878, USA 5 Colorado State University Diagnostics Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA 6 Current address: Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, Mammoth Hot Springs, Wyoming 82190, USA 7 Corresponding author (email: firstname.lastname@example.org)
Biopsy of rectal-mucosa associated lymphoid tissue provides a useful, but imperfect, live-animal test for chronic wasting disease (CWD) in mule deer (Odocoileus hemionus). It is difficult and expensive to complete these tests on free-ranging animals, and wildlife health managers will benefit from methods that can accommodate test results of varying quality. To this end, we developed a hierarchical Bayesian model to estimate the probability that an individual is infected based on test results. Our model was estimated with the use of data on 210 adult female mule deer repeatedly tested during 201022014. The ability to identify infected individuals correctly declined with age and may have been influenced by repeated biopsy. Fewer isolated lymphoid follicles (where PrPCWD accumulates) were obtained in biopsies of older deer and the proportion of follicles showing PrPCWD was reduced. A deer’s genotype in the prion gene (PRNP) also influenced detection. At least five follicles were needed in a biopsy to assure a 95% accurate test in PRNP genotype 225SS deer.
Key words: Bayesian, capture–mark–recapture, chronic wasting disease, mule deer, prion, test sensitivity.
Reliably detecting prion infection in mule deer requires some consideration of sample quality. Our findings resemble earlier work suggesting examination of at least nine lymphoid follicles in a tonsil biopsy might be necessary to determine CWD status in mule deer accurately (Wolfe et al. 2002).We found that examining five follicles in a rectal biopsy of 225SS mule deer, regardless of age, should ensure 95% probability of an accurate test; negative results were less conclusive for deer genotypes including phenylalanine (225SF, 225FF). Importantly, examining fewer follicles provided meaningful, but less certain information about that disease status of the individual. For example, fewer than five follicles were observed in 13 of 31 (42%) tests on animals that were confirmed PrPCWD negative postmortem. These less-conclusive live tests ensured 61% probability of the correct result when one follicle was obtained, that increased to 82% with two follicles, 91% with three, and 94%with four. Likewise, we encountered four apparent false-negative results in 225SS deer. In each case, we could not ensure a 95% accurate test based on deer age and numbers of follicles in biopsies.
Rarely have individual animals infected with prion disease been repeatedly tested after a positive test. Instead, infected animals have generally been presumed to remain positive if retested because postmortem exams have confirmed their infection status (e.g.,Wolfe et al. 2007; Gona´ lez et al. 2008). This belief appears well-founded based on evidence that prion diseases are progressive and that the proportion of positive lymphoid follicles increases over the course of infection (e.g., Fox et al. 2006). Given this well established pattern, we were surprised that nearly half of the follow-up biopsies collected from deer that had already yielded a positive biopsy were negative.
Repeated biopsy of the rectal mucosa may have given rise to these false-negative tests. Isolated lymphoid follicles show dynamic properties, including de novo formation in adult animals (Lorenz et al. 2003). Gut-associated lymphoid tissue serves a variety of mucosal barrier defense functions, and isolated lymphoid follicles have been suggested to play a role in mucosal repair (Sipos et al. 2010). If the damage resulting from a biopsy stimulated new isolated lymphoid follicles to form in adjacent rectal mucosa, then the follicles available for subsequent sampling would be a mix of newer and older follicles. Because new follicles (#12 mo old) would not have the same opportunity for prion accumulation as older follicles, their presence in nearby spans of mucosa could dilute or supplant the IHC-positive follicle pool in subsequent samples even as PrPCWD accumulation progressed unabated in static lymphoid structures that remain undisturbed. This phenomenon could explain the static or declining proportion of positive follicles observed in biopsies from some infected individuals that were repeatedly sampled (Fig. 4) as well as the pattern of increasing follicle counts in repeatedly sampled individuals in the face of aging (Fig. 3). If isolated lymphoid follicle formation occurs in response to rectal mucosa biopsy, then repeated sampling could lower the likelihood of detecting infected animals, particularly in individuals genetically inclined toward more gradual disease progression. Alternatively, we implicitly assumed no laboratory errors occurred in the processing of biopsy samples. However, because three of the four false-negative cases came from the same year’s IHC accession, we cannot preclude the possibility of a systematic error somewhere in the course of testing.
The decline in the proportion of isolated lymphoid follicles showing PrPCWD in older deer did not appear to be solely the result of repeated testing and associated disruption of tissue structure. Among eight deer that were biopsy positive on first testing, the proportion of follicles showing PrPCWD in 122-yr-old deer was 100% (n52), whereas proportions ranged from 272100% (mean of proportions 63%) in $3-yr-old deer (n56). We speculate that the higher proportion of positive follicles in young mule deer may result from greater activity in the immature lymphatic system or greater exposure because of close association with an infected dam or contaminated environment. Regardless of whether the foregoing observations were an artifact of small sample size, in the absence of repeated biopsy, age appeared to decrease ability to detect infection because fewer isolated lymphoid follicles were obtained in biopsies of older deer.
Every test sample is not the same; each individual exhibits unique variation, and the technique for estimating CWD infection that we developed here can account for some of these complications. Disease status becomes a probabilistic statement conditioned on the current test result, previous disease status, and infection and test sensitivity probabilities. Therefore, uncertainty in sampling becomes incorporated into the placement of individuals into discrete disease categories. This step forward allows us to make explicit probabilistic statements
0 JOURNAL OF WILDLIFE DISEASES, VOL. 51, NO. 4, OCTOBER 2015
about whether an individual is infected and the chance that a test result is correct. With CWD, rather than conclude that an individual is not infected based on a test with few follicles or decide that the test was inconclusive, we can now state the probability that an individual is truly infected. Consequently, we can make conclusions that ‘‘a 90% chance exists that this deer is not infected, based on the results.’’
Surveillance and containment programs for CWD benefit from an ability to diagnose animals correctly with the use of antemortem tests. Our model can easily be applied to surveillance on mule deer, facilitating use of all available samples regardless of total follicle counts. Probabilistic estimates of the infection status of each tested individual could then be used to provide 95% credible intervals of population prevalence that account for differences in test quality. Our model is robust to differences in population prevalence except when prevalence is low (e.g., ,0.02%), because the detection and infection parameters become inestimable. When planning surveillance in areas where disease may not occur, we recommend assuming values for the test detection parameters to allow for estimation of population prevalence. Our approach also has application to CWD screening for transport of wild or captive deer or targeted culling efforts. Individuals could be identified that require additional testing to confirm disease status with desired levels of certainty, although our approach cannot account for misdiagnosing deer in early stages of infection when PrPCWD is undetectable (Wolfe et al. 2002, 2007). In light of our findings, further attention to the potential for repeated sampling to lower the probability of detecting infection via rectal mucosa biopsy appears warranted before such approaches are substituted for more conventional surveillance that relies on samples collected postmortem.
Friday, August 28, 2015
Chronic Wasting Disease CWD TSE Prion Diagnostics and subclinical infection
Zoonotic Potential of CWD Prions
Liuting Qing1, Ignazio Cali1,2, Jue Yuan1, Shenghai Huang3, Diane Kofskey1, Pierluigi Gambetti1, Wenquan Zou1, Qingzhong Kong1 1Case Western Reserve University, Cleveland, Ohio, USA, 2Second University of Naples, Naples, Italy, 3Encore Health Resources, Houston, Texas, USA
Chronic wasting disease (CWD) is a widespread and expanding prion disease in free-ranging and captive cervid species in North America. The zoonotic potential of CWD prions is a serious public health concern. Current literature generated with in vitro methods and in vivo animal models (transgenic mice, macaques and squirrel monkeys) reports conflicting results. The susceptibility of human CNS and peripheral organs to CWD prions remains largely unresolved. In our earlier bioassay experiments using several humanized transgenic mouse lines, we detected protease-resistant PrPSc in the spleen of two out of 140 mice that were intracerebrally inoculated with natural CWD isolates, but PrPSc was not detected in the brain of the same mice. Secondary passages with such PrPSc-positive CWD-inoculated humanized mouse spleen tissues led to efficient prion transmission with clear clinical and pathological signs in both humanized and cervidized transgenic mice. Furthermore, a recent bioassay with natural CWD isolates in a new humanized transgenic mouse line led to clinical prion infection in 2 out of 20 mice. These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.
***These results indicate that the CWD prion has the potential to infect human CNS and peripheral lymphoid tissues and that there might be asymptomatic human carriers of CWD infection.***
P.105: RT-QuIC models trans-species prion transmission
Kristen Davenport, Davin Henderson, Candace Mathiason, and Edward Hoover Prion Research Center; Colorado State University; Fort Collins, CO USA
The propensity for trans-species prion transmission is related to the structural characteristics of the enciphering and heterologous PrP, but the exact mechanism remains mostly mysterious. Studies of the effects of primary or tertiary prion protein structures on trans-species prion transmission have relied primarily upon animal bioassays, making the influence of prion protein structure vs. host co-factors (e.g. cellular constituents, trafficking, and innate immune interactions) difficult to dissect. As an alternative strategy, we used real-time quakinginduced conversion (RT-QuIC) to investigate trans-species prion conversion.
To assess trans-species conversion in the RT-QuIC system, we compared chronic wasting disease (CWD) and bovine spongiform encephalopathy (BSE) prions, as well as feline CWD (fCWD) and feline spongiform encephalopathy (FSE). Each prion was seeded into each host recombinant PrP (full-length rPrP of white-tailed deer, bovine or feline). We demonstrated that fCWD is a more efficient seed for feline rPrP than for white-tailed deer rPrP, which suggests adaptation to the new host.
Conversely, FSE maintained sufficient BSE characteristics to more efficiently convert bovine rPrP than feline rPrP. Additionally, human rPrP was competent for conversion by CWD and fCWD. ***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.
***This insinuates that, at the level of protein:protein interactions, the barrier preventing transmission of CWD to humans is less robust than previously estimated.***
*** human cwd will NOT look like nvCJD damn’t. in fact, it most likely will look like the most common human TSE prion disease i.e. sporadic CJD 85%+ of all human TSE prion disease, sporadic CJD simply meaning from unknown route and source, it DOES NOT MEAN A SPONTANEOUS HAPPENING. as with iatrogenic CJD, all iatrogenic CJD is now, is sporadic CJD, until the iatrogenic event is discovered, documented and put into the academic and then public domain, which very seldom happens due to lack of documentations of such said events, and trace back efforts there from. please see ;
*** 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).***
HIGHEST INFECTION RATE ON SEVERAL CWD CONFIRMED CAPTIVES
CHRONIC WASTING DISEASE CWD WISCONSIN Almond Deer (Buckhorn Flats) Farm Update DECEMBER 2011
The CWD infection rate was nearly 80%, the highest ever in a North American captive herd.
RECOMMENDATION: That the Board approve the purchase of 80 acres of land for $465,000 for the Statewide Wildlife Habitat Program in Portage County and approve the restrictions on public use of the site.
For Immediate Release Thursday, October 2, 2014
Dustin Vande Hoef 515/281-3375 or 515/326-1616 (cell) or Dustin.VandeHoef@IowaAgriculture.gov
*** TEST RESULTS FROM CAPTIVE DEER HERD WITH CHRONIC WASTING DISEASE RELEASED 79.8 percent of the deer tested positive for the disease
DES MOINES – The Iowa Department of Agriculture and Land Stewardship today announced that the test results from the depopulation of a quarantined captive deer herd in north-central Iowa showed that 284 of the 356 deer, or 79.8% of the herd, tested positive for Chronic Wasting Disease (CWD).
*** see history of this CWD blunder here ;
On June 5, 2013, DNR conducted a fence inspection, after gaining approval from surrounding landowners, and confirmed that the fenced had been cut or removed in at least four separate locations; that the fence had degraded and was failing to maintain the enclosure around the Quarantined Premises in at least one area; that at least three gates had been opened;and that deer tracks were visible in and around one of the open areas in the sand on both sides of the fence, evidencing movement of deer into the Quarantined Premises.
The overall incidence of clinical CWD in white-tailed deer was 82%
Species (cohort) CWD (cases/total) Incidence (%) Age at CWD death (mo)
CWD, spreading it around...
for the game farm industry, and their constituents, to continue to believe that they are _NOT_, and or insinuate that they have _NEVER_ been part of the problem, will only continue to help spread cwd. the game farming industry, from the shooting pens, to the urine mills, the antler mills, the sperm mills, velvet mills, shooting pens, to large ranches, are not the only problem, but it is painfully obvious that they have been part of the problem for decades and decades, just spreading it around, as with transportation and or exportation and or importation of cervids from game farming industry, and have been proven to spread cwd. no one need to look any further than South Korea blunder ;
spreading cwd around...
Between 1996 and 2002, chronic wasting disease was diagnosed in 39 herds of farmed elk in Saskatchewan in a single epidemic. All of these herds were depopulated as part of the Canadian Food Inspection Agency’s (CFIA) disease eradication program. Animals, primarily over 12 mo of age, were tested for the presence CWD prions following euthanasia. Twenty-one of the herds were linked through movements of live animals with latent CWD from a single infected source herd in Saskatchewan, 17 through movements of animals from 7 of the secondarily infected herds.
***The source herd is believed to have become infected via importation of animals from a game farm in South Dakota where CWD was subsequently diagnosed (7,4). A wide range in herd prevalence of CWD at the time of herd depopulation of these herds was observed. Within-herd transmission was observed on some farms, while the disease remained confined to the introduced animals on other farms.
spreading cwd around...
Friday, May 13, 2011
Chronic Wasting Disease (CWD) outbreaks and surveillance program in the Republic of Korea
Hyun-Joo Sohn, Yoon-Hee Lee, Min-jeong Kim, Eun-Im Yun, Hyo-Jin Kim, Won-Yong Lee, Dong-Seob Tark, In- Soo Cho, Foreign Animal Disease Research Division, National Veterinary Research and Quarantine Service, Republic of Korea
Chronic wasting disease (CWD) has been recognized as an important prion disease in native North America deer and Rocky mountain elks. The disease is a unique member of the transmissible spongiform encephalopathies (TSEs), which naturally affects only a few species. CWD had been limited to USA and Canada until 2000.
On 28 December 2000, information from the Canadian government showed that a total of 95 elk had been exported from farms with CWD to Korea. These consisted of 23 elk in 1994 originating from the so-called “source farm” in Canada, and 72 elk in 1997, which had been held in pre export quarantine at the “source farm”.Based on export information of CWD suspected elk from Canada to Korea, CWD surveillance program was initiated by the Ministry of Agriculture and Forestry (MAF) in 2001.
All elks imported in 1997 were traced back, however elks imported in 1994 were impossible to identify. CWD control measures included stamping out of all animals in the affected farm, and thorough cleaning and disinfection of the premises. In addition, nationwide clinical surveillance of Korean native cervids, and improved measures to ensure reporting of CWD suspect cases were implemented.
Total of 9 elks were found to be affected. CWD was designated as a notifiable disease under the Act for Prevention of Livestock Epidemics in 2002.
Additional CWD cases - 12 elks and 2 elks - were diagnosed in 2004 and 2005.
Since February of 2005, when slaughtered elks were found to be positive, all slaughtered cervid for human consumption at abattoirs were designated as target of the CWD surveillance program. Currently, CWD laboratory testing is only conducted by National Reference Laboratory on CWD, which is the Foreign Animal Disease Division (FADD) of National Veterinary Research and Quarantine Service (NVRQS).
In July 2010, one out of 3 elks from Farm 1 which were slaughtered for the human consumption was confirmed as positive. Consequently, all cervid – 54 elks, 41 Sika deer and 5 Albino deer – were culled and one elk was found to be positive. Epidemiological investigations were conducted by Veterinary Epidemiology Division (VED) of NVRQS in collaboration with provincial veterinary services.
Epidemiologically related farms were found as 3 farms and all cervid at these farms were culled and subjected to CWD diagnosis. Three elks and 5 crossbreeds (Red deer and Sika deer) were confirmed as positive at farm 2.
All cervids at Farm 3 and Farm 4 – 15 elks and 47 elks – were culled and confirmed as negative.
Further epidemiological investigations showed that these CWD outbreaks were linked to the importation of elks from Canada in 1994 based on circumstantial evidences.
In December 2010, one elk was confirmed as positive at Farm 5. Consequently, all cervid – 3 elks, 11 Manchurian Sika deer and 20 Sika deer – were culled and one Manchurian Sika deer and seven Sika deer were found to be positive. This is the first report of CWD in these sub-species of deer. Epidemiological investigations found that the owner of the Farm 2 in CWD outbreaks in July 2010 had co-owned the Farm 5.
In addition, it was newly revealed that one positive elk was introduced from Farm 6 of Jinju-si Gyeongsang Namdo. All cervid – 19 elks, 15 crossbreed (species unknown) and 64 Sika deer – of Farm 6 were culled, but all confirmed as negative.
*** Spraker suggested an interesting explanation for the occurrence of CWD. The deer pens at the Foot Hills Campus were built some 30-40 years ago by a Dr. Bob Davis. At or abut that time, allegedly, some scrapie work was conducted at this site. When deer were introduced to the pens they occupied ground that had previously been occupied by sheep.
New studies on the heat resistance of hamster-adapted scrapie agent: Threshold survival after ashing at 600°C suggests an inorganic template of replication
The infectious agents responsible for transmissible spongiform encephalopathy (TSE) are notoriously resistant to most physical and chemical methods used for inactivating pathogens, including heat. It has long been recognized, for example, that boiling is ineffective and that higher temperatures are most efficient when combined with steam under pressure (i.e., autoclaving). As a means of decontamination, dry heat is used only at the extremely high temperatures achieved during incineration, usually in excess of 600°C. It has been assumed, without proof, that incineration totally inactivates the agents of TSE, whether of human or animal origin.
Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production
Histochemical analysis of hamster brains inoculated with the solid residue showed typical spongiform degeneration and vacuolation. Re-inoculation of these brains into a new cohort of hamsters led to onset of clinical scrapie symptoms within 75 days, suggesting that the specific infectivity of the prion protein was not changed during the biodiesel process. The biodiesel reaction cannot be considered a viable prion decontamination method for MBM, although we observed increased survival time of hamsters and reduced infectivity greater than 6 log orders in the solid MBM residue. Furthermore, results from our study compare for the first time prion detection by Western Blot versus an infectivity bioassay for analysis of biodiesel reaction products. We could show that biochemical analysis alone is insufficient for detection of prion infectivity after a biodiesel process.
Detection of protease-resistant cervid prion protein in water from a CWD-endemic area
The data presented here demonstrate that sPMCA can detect low levels of PrPCWD in the environment, corroborate previous biological and experimental data suggesting long term persistence of prions in the environment2,3 and imply that PrPCWD accumulation over time may contribute to transmission of CWD in areas where it has been endemic for decades. This work demonstrates the utility of sPMCA to evaluate other environmental water sources for PrPCWD, including smaller bodies of water such as vernal pools and wallows, where large numbers of cervids congregate and into which prions from infected animals may be shed and concentrated to infectious levels.
A Quantitative Assessment of the Amount of Prion Diverted to Category 1 Materials and Wastewater During Processing
Keywords:Abattoir;bovine spongiform encephalopathy;QRA;scrapie;TSE
In this article the development and parameterization of a quantitative assessment is described that estimates the amount of TSE infectivity that is present in a whole animal carcass (bovine spongiform encephalopathy [BSE] for cattle and classical/atypical scrapie for sheep and lambs) and the amounts that subsequently fall to the floor during processing at facilities that handle specified risk material (SRM). BSE in cattle was found to contain the most oral doses, with a mean of 9864 BO ID50s (310, 38840) in a whole carcass compared to a mean of 1851 OO ID50s (600, 4070) and 614 OO ID50s (155, 1509) for a sheep infected with classical and atypical scrapie, respectively. Lambs contained the least infectivity with a mean of 251 OO ID50s (83, 548) for classical scrapie and 1 OO ID50s (0.2, 2) for atypical scrapie. The highest amounts of infectivity falling to the floor and entering the drains from slaughtering a whole carcass at SRM facilities were found to be from cattle infected with BSE at rendering and large incineration facilities with 7.4 BO ID50s (0.1, 29), intermediate plants and small incinerators with a mean of 4.5 BO ID50s (0.1, 18), and collection centers, 3.6 BO ID50s (0.1, 14). The lowest amounts entering drains are from lambs infected with classical and atypical scrapie at intermediate plants and atypical scrapie at collection centers with a mean of 3 × 10−7 OO ID50s (2 × 10−8, 1 × 10−6) per carcass. The results of this model provide key inputs for the model in the companion paper published here.
*** Infectious agent of sheep scrapie may persist in the environment for at least 16 years ***
Gudmundur Georgsson1, Sigurdur Sigurdarson2 and Paul Brown3
cwd environmental load factor in the land and surrounding plants and objects.
transportation of cervids and HUMANS from cwd zone should be regarded as a great risk factor, and environmental contamination.
Using in vitro prion replication for high sensitive detection of prions and prionlike proteins and for understanding mechanisms of transmission.
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.
98 | Veterinary Record | January 24, 2015
Scrapie: a particularly persistent pathogen
Resistant prions in the environment have been the sword of Damocles for scrapie control and eradication. Attempts to establish which physical and chemical agents could be applied to inactivate or moderate scrapie infectivity were initiated in the 1960s and 1970s,with the first study of this type focusing on the effect of heat treatment in reducing prion infectivity (Hunter and Millson 1964). Nowadays, most of the chemical procedures that aim to inactivate the prion protein are based on the method developed by Kimberlin and collaborators (1983). This procedure consists of treatment with 20,000 parts per million free chlorine solution, for a minimum of one hour, of all surfaces that need to be sterilised (in laboratories, lambing pens, slaughterhouses, and so on). Despite this, veterinarians and farmers may still ask a range of questions, such as ‘Is there an official procedure published somewhere?’ and ‘Is there an international organisation which recommends and defines the exact method of scrapie decontamination that must be applied?’
From a European perspective, it is difficult to find a treatment that could be applied, especially in relation to the disinfection of surfaces in lambing pens of affected flocks. A 999/2001 EU regulation on controlling spongiform encephalopathies (European Parliament and Council 2001) did not specify a particular decontamination measure to be used when an outbreak of scrapie is diagnosed. There is only a brief recommendation in Annex VII concerning the control and eradication of transmissible spongiform encephalopathies (TSE s).
Chapter B of the regulation explains the measures that must be applied if new caprine animals are to be introduced to a holding where a scrapie outbreak has previously been diagnosed. In that case, the statement indicates that caprine animals can be introduced ‘provided that a cleaning and disinfection of all animal housing on the premises has been carried out following destocking’.
Issues around cleaning and disinfection are common in prion prevention recommendations, but relevant authorities, veterinarians and farmers may have difficulties in finding the specific protocol which applies. The European Food and Safety Authority (EFSA ) published a detailed report about the efficacy of certain biocides, such as sodium hydroxide, sodium hypochlorite, guanidine and even a formulation of copper or iron metal ions in combination with hydrogen peroxide, against prions (EFSA 2009). The report was based on scientific evidence (Fichet and others 2004, Lemmer and others 2004, Gao and others 2006, Solassol and others 2006) but unfortunately the decontamination measures were not assessed under outbreak conditions.
The EFSA Panel on Biological Hazards recently published its conclusions on the scrapie situation in the EU after 10 years of monitoring and control of the disease in sheep and goats (EFSA 2014), and one of the most interesting findings was the Icelandic experience regarding the effect of disinfection in scrapie control. The Icelandic plan consisted of: culling scrapie-affected sheep or the whole flock in newly diagnosed outbreaks; deep cleaning and disinfection of stables, sheds, barns and equipment with high pressure washing followed by cleaning with 500 parts per million of hypochlorite; drying and treatment with 300 ppm of iodophor; and restocking was not permitted for at least two years. Even when all of these measures were implemented, scrapie recurred on several farms, indicating that the infectious agent survived for years in the environment, even as many as 16 years after restocking (Georgsson and others 2006).
In the rest of the countries considered in the EFSA (2014) report, recommendations for disinfection measures were not specifically defined at the government level. In the report, the only recommendation that is made for sheep is repopulation with sheep with scrapie-resistant genotypes. This reduces the risk of scrapie recurrence but it is difficult to know its effect on the infection.
Until the EFSA was established (in May 2003), scientific opinions about TSE s were provided by the Scientific Steering Committee (SSC) of the EC, whose advice regarding inactivation procedures focused on treating animal waste at high temperatures (150°C for three hours) and high pressure alkaline hydrolysis (SSC 2003). At the same time, the TSE Risk Management Subgroup of the Advisory Committee on Dangerous Pathogens (ACDP) in the UK published guidance on safe working and the prevention of TSE infection. Annex C of the ACDP report established that sodium hypochlorite was considered to be effective, but only if 20,000 ppm of available chlorine was present for at least one hour, which has practical limitations such as the release of chlorine gas, corrosion, incompatibility with formaldehyde, alcohols and acids, rapid inactivation of its active chemicals and the stability of dilutions (ACDP 2009).
In an international context, the World Organisation for Animal Health (OIE) does not recommend a specific disinfection protocol for prion agents in its Terrestrial Code or Manual. Chapter 4.13 of the Terrestrial Code, General recommendations on disinfection and disinsection (OIE 2014), focuses on foot-and-mouth disease virus, mycobacteria and Bacillus anthracis, but not on prion disinfection. Nevertheless, the last update published by the OIE on bovine spongiform encephalopathy (OIE 2012) indicates that few effective decontamination techniques are available to inactivate the agent on surfaces, and recommends the removal of all organic material and the use of sodium hydroxide, or a sodium hypochlorite solution containing 2 per cent available chlorine, for more than one hour at 20ºC.
The World Health Organization outlines guidelines for the control of TSE s, and also emphasises the importance of mechanically cleaning surfaces before disinfection with sodium hydroxide or sodium hypochlorite for one hour (WHO 1999).
Finally, the relevant agencies in both Canada and the USA suggest that the best treatments for surfaces potentially contaminated with prions are sodium hydroxide or sodium hypochlorite at 20,000 ppm. This is a 2 per cent solution, while most commercial household bleaches contain 5.25 per cent sodium hypochlorite. It is therefore recommended to dilute one part 5.25 per cent bleach with 1.5 parts water (CDC 2009, Canadian Food Inspection Agency 2013).
So what should we do about disinfection against prions? First, it is suggested that a single protocol be created by international authorities to homogenise inactivation procedures and enable their application in all scrapie-affected countries. Sodium hypochlorite with 20,000 ppm of available chlorine seems to be the procedure used in most countries, as noted in a paper summarised on p 99 of this issue of Veterinary Record (Hawkins and others 2015). But are we totally sure of its effectiveness as a preventive measure in a scrapie outbreak? Would an in-depth study of the recurrence of scrapie disease be needed?
What we can conclude is that, if we want to fight prion diseases, and specifically classical scrapie, we must focus on the accuracy of diagnosis, monitoring and surveillance; appropriate animal identification and control of movements; and, in the end, have homogeneous and suitable protocols to decontaminate and disinfect lambing barns, sheds and equipment available to veterinarians and farmers. Finally, further investigations into the resistance of prion proteins in the diversity of environmental surfaces are required.
98 | Veterinary Record | January 24, 2015
Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination
Steve A. C. Hawkins, MIBiol, Pathology Department1, Hugh A. Simmons, BVSc MRCVS, MBA, MA Animal Services Unit1, Kevin C. Gough, BSc, PhD2 and Ben C. Maddison, BSc, PhD3 + Author Affiliations
1Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK 2School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK 3ADAS UK, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK E-mail for correspondence: email@example.com Abstract Scrapie of sheep/goats and chronic wasting disease of deer/elk are contagious prion diseases where environmental reservoirs are directly implicated in the transmission of disease. In this study, the effectiveness of recommended scrapie farm decontamination regimens was evaluated by a sheep bioassay using buildings naturally contaminated with scrapie. Pens within a farm building were treated with either 20,000 parts per million free chorine solution for one hour or were treated with the same but were followed by painting and full re-galvanisation or replacement of metalwork within the pen. Scrapie susceptible lambs of the PRNP genotype VRQ/VRQ were reared within these pens and their scrapie status was monitored by recto-anal mucosa-associated lymphoid tissue. All animals became infected over an 18-month period, even in the pen that had been subject to the most stringent decontamination process. These data suggest that recommended current guidelines for the decontamination of farm buildings following outbreaks of scrapie do little to reduce the titre of infectious scrapie material and that environmental recontamination could also be an issue associated with these premises.
Thorough pressure washing of a pen had no effect on the amount of bioavailable scrapie infectivity (pen B). The routine removal of prions from surfaces within a laboratory setting is treatment for a minimum of one hour with 20,000 ppm free chlorine, a method originally based on the use of brain macerates from infected rodents to evaluate the effectiveness of decontamination (Kimberlin and others 1983). Further studies have also investigated the effectiveness of hypochlorite disinfection of metal surfaces to simulate the decontamination of surgical devices within a hospital setting. Such treatments with hypochlorite solution were able to reduce infectivity by 5.5 logs to lower than the sensitivity of the bioassay used (Lemmer and others 2004). Analogous treatment of the pen surfaces did not effectively remove the levels of scrapie infectivity over that of the control pens, indicating that this method of decontamination is not effective within a farm setting. This may be due to the high level of biological matrix that is present upon surfaces within the farm environment, which may reduce the amount of free chlorine available to inactivate any infectious prion. Remarkably 1/5 sheep introduced into pen D had also became scrapie positive within nine months, with all animals in this pen being RAMALT positive by 18 months of age. Pen D was no further away from the control pen (pen A) than any of the other pens within this barn. Localised hot spots of infectivity may be present within scrapie-contaminated environments, but it is unlikely that pen D area had an amount of scrapie contamination that was significantly different than the other areas within this building. Similarly, there were no differences in how the biosecurity of pen D was maintained, or how this pen was ventilated compared with the other pens. This observation, perhaps, indicates the slower kinetics of disease uptake within this pen and is consistent with a more thorough prion removal and recontamination. These observations may also account for the presence of inadvertent scrapie cases within other studies, where despite stringent biosecurity, control animals have become scrapie positive during challenge studies using barns that also housed scrapie-affected animals (Ryder and others 2009). The bioassay data indicate that the exposure of the sheep to a farm environment after decontamination efforts thought to be effective in removing scrapie is sufficient for the animals to become infected with scrapie. The main exposure routes within this scenario are likely to be via the oral route, during feeding and drinking, and respiratory and conjunctival routes. It has been demonstrated that scrapie infectivity can be efficiently transmitted via the nasal route in sheep (Hamir and others 2008), as is the case for CWD in both murine models and in white-tailed deer (Denkers and others 2010, 2013). Recently, it has also been demonstrated that CWD prions presented as dust when bound to the soil mineral montmorillonite can be infectious via the nasal route (Nichols and others 2013). When considering pens C and D, the actual source of the infectious agent in the pens is not known, it is possible that biologically relevant levels of prion survive on surfaces during the decontamination regimen (pen C). With the use of galvanising and painting (pen D) covering and sealing the surface of the pen, it is possible that scrapie material recontaminated the pens by the movement of infectious prions contained within dusts originating from other parts of the barn that were not decontaminated or from other areas of the farm.
Given that scrapie prions are widespread on the surfaces of affected farms (Maddison and others 2010a), irrespective of the source of the infectious prions in the pens, this study clearly highlights the difficulties that are faced with the effective removal of environmentally associated scrapie infectivity. This is likely to be paralleled in CWD which shows strong similarities to scrapie in terms of both the dissemination of prions into the environment and the facile mode of disease transmission. These data further contribute to the understanding that prion diseases can be highly transmissible between susceptible individuals not just by direct contact but through highly stable environmental reservoirs that are refractory to decontamination.
The presence of these environmentally associated prions in farm buildings make the control of these diseases a considerable challenge, especially in animal species such as goats where there is lack of genetic resistance to scrapie and, therefore, no scope to re-stock farms with animals that are resistant to scrapie.
Scrapie Sheep Goats Transmissible spongiform encephalopathies (TSE) Accepted October 12, 2014. Published Online First 31 October 2014
Monday, November 3, 2014
Persistence of ovine scrapie infectivity in a farm environment following cleaning and decontamination
Detection of Environmentally Associated PrPSc on a Farm with Endemic Scrapie
Ben C. Maddison,1 Claire A. Baker,1 Helen C. Rees,1 Linda A. Terry,2 Leigh Thorne,2 Susan J. Belworthy2 and Kevin C. Gough3 1ADAS-UK LTD; Department of Biology; University of Leicester; Leicester, UK; 2Veterinary Laboratories Agency; Surry, KT UK; 3Department of Veterinary Medicine and Science; University of Nottingham; Sutton Bonington, Loughborough UK
Key words: scrapie, evironmental persistence, sPMCA
Ovine scrapie shows considerable horizontal transmission, yet the routes of transmission and specifically the role of fomites in transmission remain poorly defined. Here we present biochemical data demonstrating that on a scrapie-affected sheep farm, scrapie prion contamination is widespread. It was anticipated at the outset that if prions contaminate the environment that they would be there at extremely low levels, as such the most sensitive method available for the detection of PrPSc, serial Protein Misfolding Cyclic Amplification (sPMCA), was used in this study. We investigated the distribution of environmental scrapie prions by applying ovine sPMCA to samples taken from a range of surfaces that were accessible to animals and could be collected by use of a wetted foam swab. Prion was amplified by sPMCA from a number of these environmental swab samples including those taken from metal, plastic and wooden surfaces, both in the indoor and outdoor environment. At the time of sampling there had been no sheep contact with these areas for at least 20 days prior to sampling indicating that prions persist for at least this duration in the environment. These data implicate inanimate objects as environmental reservoirs of prion infectivity which are likely to contribute to disease transmission.
Willingham, Erin McNulty, Kelly Anderson, Jeanette Hayes-Klug, Amy Nalls, and Candace Mathiason Colorado State University; Fort Collins, CO USA
Chronic wasting disease (CWD) is the transmissible spongiform encephalopathy (TSE), of free-ranging and captive cervids (deer, elk and moose).
The presence of infectious prions in the tissues, bodily fluids and environments of clinical and preclinical CWD-infected animals is thought to account for its high transmission efficiency. Recently it has been recognized that mother to offspring transmission may contribute to the facile transmission of some TSEs. Although the mechanism behind maternal transmission is not yet known, the extended asymptomatic TSE carrier phase (lasting years to decades) suggests that it may have implications in the spread of prions.
Placental trafficking and/or secretion in milk are 2 means by which maternal prion transmission may occur. In these studies we explore these avenues during early and late infection using a transgenic mouse model expressing cervid prion protein. Na€ıve and CWD-infected dams were bred at both timepoints, and were allowed to bear and raise their offspring. Milk was collected from the dams for prion analysis, and the offspring were observed for TSE disease progression. Terminal tissues harvested from both dams and offspring were analyzed for prions.
We have demonstrated that
(1) CWDinfected TgCerPRP females successfully breed and bear offspring, and
(2) the presence of PrPCWD in reproductive and mammary tissue from CWD-infected dams.
We are currently analyzing terminal tissue harvested from offspring born to CWD-infected dams for the detection of PrPCWD and amplification competent prions. These studies will provide insight into the potential mechanisms and biological significance associated with mother to offspring transmission of TSEs.
P.157: Uptake of prions into plants
Christopher Johnson1, Christina Carlson1, Matthew Keating1,2, Nicole Gibbs1, Haeyoon Chang1, Jamie Wiepz1, and Joel Pedersen1 1USGS National Wildlife Health Center; Madison, WI USA; 2University of Wisconsin - Madison; Madison, WI USA
Soil may preserve chronic wasting disease (CWD) and scrapie infectivity in the environment, making consumption or inhalation of soil particles a plausible mechanism whereby na€ıve animals can be exposed to prions. Plants are known to absorb a variety of substances from soil, including whole proteins, yet the potential for plants to take up abnormal prion protein (PrPTSE) and preserve prion infectivity is not known. In this study, we assessed PrPTSE uptake into roots using laser scanning confocal microscopy with fluorescently tagged PrPTSE and we used serial protein misfolding cyclic amplification (sPMCA) and detect and quantify PrPTSE levels in plant aerial tissues. Fluorescence was identified in the root hairs of the model plant Arabidopsis thaliana, as well as the crop plants alfalfa (Medicago sativa), barley (Hordeum vulgare) and tomato (Solanum lycopersicum) upon exposure to tagged PrPTSE but not a tagged control preparation. Using sPMCA, we found evidence of PrPTSE in aerial tissues of A. thaliana, alfalfa and maize (Zea mays) grown in hydroponic cultures in which only roots were exposed to PrPTSE. Levels of PrPTSE in plant aerial tissues ranged from approximately 4 £ 10 ¡10 to 1 £ 10 ¡9 g PrPTSE g ¡1 plant dry weight or 2 £ 105 to 7 £ 106 intracerebral ID50 units g ¡1 plant dry weight. Both stems and leaves of A. thaliana grown in culture media containing prions are infectious when intracerebrally-injected into mice. ***Our results suggest that prions can be taken up by plants and that contaminated plants may represent a previously unrecognized risk of human, domestic species and wildlife exposure to prions.
***Our results suggest that prions can be taken up by plants and that contaminated plants may represent a previously unrecognized risk of human, domestic species and wildlife exposure to prions.***
Friday, May 15, 2015
Grass Plants Bind, Retain, Uptake, and Transport Infectious Prions
P.19: Characterization of chronic wasting disease isolates from freeranging deer (Odocoileus sp) in Alberta and Saskatchewan, Canada
Camilo Duque Velasquez1, Chiye Kim1, Nathalie Daude1, Jacques van der Merwe1, Allen Herbst1, Trent Bollinger2, Judd Aiken1, and Debbie McKenzie1 1Centre for Prions and Protein Folding Diseases; University of Alberta; Edmonton, Canada; 2Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon, Canada
Chronic wasting disease (CWD) is an emerging prion disease of free ranging and captive species of Cervidae. In North America, CWD is enzootic in some wild cervid populations and can circulate among different deer species. The contagious nature of CWD prions and the variation of cervid PRNP alleles, which influence host susceptibility, can result in the emergence and adaptation of different CWD strains. These strains may impact transmission host range, disease diagnosis, spread dynamics and efficacy of potential vaccines. We are characterizing different CWD agents by biochemical analysis of the PrPCWD conformers, propagation in vitro cell assays1 and by comparing transmission properties and neuropathology in Tg33 (Q95G96) and Tg60 (Q95S96) mice.2 Although Tg60 mice expressing S96- PrPC have been shown resistant to CWD infectivity from various cervid species,2,3
***these transgenic mice are susceptible to H95 C CWD, a CWD strain derived from experimental infection of deer expressing H95G96-PrPC. The diversity of strains present in free-ranging mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) from Alberta and Saskatchewan is being determined and will allow us to delineate the properties of CWD agents circulating in CWD enzootic cervid populations of Canada.
1. van der Merwe J, Aiken J, Westaway D, McKenzie D. The standard scrapie cell assay: Development, utility and prospects. Viruses 2015; 7(1):180–198; PMID:25602372; http://dx.doi.org/10.3390/v7010180
2. Meade-White K, Race B, Trifilo M, Bossers A, Favara C, Lacasse R, Miller M, Williams E, Oldstone M, Race R, Chesebro B. Resistance to chronic wasting disease in transgenic mice expressing a naturally occurring allelic variant of deer prion protein. J Virol 2007; 81(9):4533–4539; PMID: 17314157; http://dx. doi.org/10.1128/JVI.02762-06
3. Race B, Meade-White K, Miller MW, Fox KA, Chesebro B. In vivo comparison of chronic wasting disease infectivity from deer with variation at prion protein residue 96. J Virol 2011; 85(17):9235–9238; PMID: 21697479; http://dx.doi.org/10.1128/JVI.00790-11
***these transgenic mice are susceptible to H95 C CWD, a CWD strain derived from experimental infection of deer expressing H95G96-PrPC.
P.136: Mother to offspring transmission of CWD—Detection in fawn tissues using the QuIC assay
Amy Nalls, Erin McNulty, Clare Hoover, Jeanette Hayes-Klug, Kelly Anderson, Edward Hoover, and Candace Mathiason Colorado State University; Fort Collins, CO USA
To investigate the role mother to offspring transmission plays in chronic wasting disease (CWD), we have employed a small, polyestrous breeding, indoor maintainable cervid model, the Reeves’ muntjac deer. Muntjac doe were inoculated with CWD and tested positive by lymphoid biopsy at 4 months post inoculation. From these CWD-infected doe, we obtained 3 viable fawns. These fawns tested IHC-positive for CWD by lymphoid biopsy as early as 40 d post birth, and all have been euthanized due to clinical disease at 31, 34 and 59 months post birth. The QuIC assay demonstrates sensitivity and specificity in the detection of conversion competent prions in peripheral IHC-positive tissues including tonsil, mandibular, partotid, retropharyngeal, and prescapular lymph nodes, adrenal gland, spleen and liver. In summary, using the muntjac deer model, we have demonstrated CWD clinical disease in offspring born to CWD-infected doe and found that the QuIC assay is an effective tool in the detection of prions in peripheral tissues. ***Our findings demonstrate that transmission of prions from mother to offspring can occur, and may be underestimated for all prion diseases.
***Our findings demonstrate that transmission of prions from mother to offspring can occur, and may be underestimated for all prion diseases.
P.97: Scrapie transmits to white-tailed deer by the oral route and has a molecular profile similar to chronic wasting disease and distinct from the scrapie inoculum
Justin Greenlee1, S Jo Moore1, Jodi Smith1, M Heather West Greenlee2, and Robert Kunkle1 1National Animal Disease Center; Ames, IA USA; 2Iowa State University; Ames, IA USA
The purpose of this work was to determine susceptibility of white-tailed deer (WTD) to the agent of sheep scrapie and to compare the resultant PrPSc to that of the original inoculum and chronic wasting disease (CWD). We inoculated WTD by a natural route of exposure (concurrent oral and intranasal (IN); n D 5) with a US scrapie isolate. All scrapie-inoculated deer had evidence of PrPSc accumulation. PrPSc was detected in lymphoid tissues at preclinical time points, and deer necropsied after 28 months post-inoculation had clinical signs, spongiform encephalopathy, and widespread distribution of PrPSc in neural and lymphoid tissues. Western blotting (WB) revealed PrPSc with 2 distinct molecular profiles. WB on cerebral cortex had a profile similar to the original scrapie inoculum, whereas WB of brainstem, cerebellum, or lymph nodes revealed PrPSc with a higher profile resembling CWD. Homogenates with the 2 distinct profiles from WTD with clinical scrapie were further passaged to mice expressing cervid prion protein and intranasally to sheep and WTD. In cervidized mice, the 2 inocula have distinct incubation times. Sheep inoculated intranasally with WTD derived scrapie developed disease, but only after inoculation with the inoculum that had a scrapie-like profile. The WTD study is ongoing, but deer in both inoculation groups are positive for PrPSc by rectal mucosal biopsy. In summary, this work demonstrates that WTD are susceptible to the agent of scrapie, 2 distinct molecular profiles of PrPSc are present in the tissues of affected deer, and inoculum of either profile readily passes to deer.
Saturday, January 31, 2015
European red deer (Cervus elaphus elaphus) are susceptible to Bovine Spongiform Encephalopathy BSE by Oral Alimentary route
I strenuously once again urge the FDA and its industry constituents, to make it MANDATORY that all ruminant feed be banned to all ruminants, and this should include all cervids as soon as possible for the following reasons...
In the USA, under the Food and Drug Administrations 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.
31 Jan 2015 at 20:14 GMT
*** Ruminant feed ban for cervids in the United States? ***
31 Jan 2015 at 20:14 GMT
Sunday, August 23, 2015
TAHC Chronic Wasting Disease CWD TSE Prion and how to put lipstick on a pig and take her to the dance in Texas
from the other side of the fence... today’s Singeltary Sunday School class ‘thinking outside of the box, God’s Wrath’ at the bottom. ...tss
TEXAS DEER CZAR SENT TO WISCONSIN TO SOLVE CWD CRISIS, WHILE ROME (TEXAS) BURNS
Tuesday, August 11, 2015
Wisconsin doing what it does best, procrastinating about CWD yet again thanks to Governor Walker
Monday, August 24, 2015
Ohio wildlife officials ramp up fight against fatal deer brain disease after 17 more positive tests CWD
Monday, August 31, 2015
Illinois Loosing Ground to Chronic Wasting Disease CWD cases mounting with 71 confirmed in 2015 and 538 confirmed cases to date
Saturday, September 05, 2015
Missouri Captive Cervid Industry, CWD TSE Prion, and Procrastinating for Money, while mad deer and elk disease silently spreads
Friday, August 14, 2015
Susceptibility of cattle to the agent of chronic wasting disease from elk after intracranial inoculation
Friday, August 14, 2015
Carcass Management During a Mass Animal Health Emergency Draft Programmatic Environmental Impact Statement—August 2015
Terry S. Singeltary Sr.