Enhanced Surveillance Strategies for Detecting and Monitoring Chronic Wasting Disease in Free-Ranging Cervids Open-File Report 2012–1036
Open-File Report 2012–1036
U.S.
Enhanced Surveillance Strategies for Detecting and Monitoring Chronic Wasting Disease in Free-Ranging Cervids
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In addition to locations of known CWD-positive individuals, other spatial risk factors related to CWD exposure should be considered. For example, the risk of free-ranging animals being exposed to CWD is likely greater in areas where captive cervid facilities have or had CWD-positive animals. Current evidence indicates that CWD infection rates are much higher in captive facilities than in wild populations (Keane and others, 2008), and perhaps this is driven by environmental contamination (Miller and others, 2006). This higher rate of infection in captive animals can increase the risk of disease exposure to surrounding wild populations. Furthermore, movement of infectious animals, carcasses, or other materials across the landscape, naturally or with human assistance, likely increases the risk to uninfected populations. The frequent movement of farmed elk (Cervus elaphus) and deer between production facilities, the concentration of infected animals on some facilities, and the possibility of their escape into the wild increases the risk of spreading CWD to uninfected populations of free-ranging animals. Because the infectious prions may persist in the environment for long periods, the introduction of either captive or free-ranging uninfected animals into a contaminated environment could increase their risk of infection. For example, locations from which sheep have been removed may remain contaminated with scrapie agent for more than 15 years (Georgsson and others, 2006). In a similar manner, translocation of cervids from areas that have not been documented to be CWD-free could pose a risk of disease introduction. In this situation, the risk of introduction is likely related to the probability of infected animals being moved and their ability to spread CWD to other susceptible animals or into the environment. Thus, surveillance on and around cervid farms or free-ranging populations that have received animals from known CWD areas and bordering jurisdictions with CWD-positive animals can increase the likelihood of disease spread. Additional risk factors, such as the presence of scrapie in sheep populations that are sympatric with deer and elk (Greenlee and others, 2011), feeding of animal protein to cervids (Johnson, McKenzie, and others, 2011), baiting and feeding programs (Thompson and others, 2008), or other environmental factors also may be considered, although their roles in CWD epidemiology has not been clearly established.
The soil composition of a region may also play an important role in the occurrence and maintenance of CWD and other TSEs (Smith and others, 2011). Recently, it has been shown that certain soil types can chemically bind and increase infectivity of prion protein (PrP), creating the potential for the protein to be maintained at the soil surface for uptake by foraging animals (Johnson and others, 2006; Johnson and others, 2007; Polano and others, 2008; Imrie, 2009); however, the fate of prions may be highly dependent on source of deposition into the soil (for example, fluid or tissue; Saunders and others 2009). In addition, organic soil components (humic acids) appear to enhance the adsorption of PrP to clay minerals and show a great affinity for the protein as well; however, it is unclear whether the effect of the organic matter increases or decreases infectivity (Polano and others, 2008). The importance of soil in CWD epidemiology was reaffirmed by Walter and others (2011) who demonstrated an 8.9-percent increase in an individual’s deer’s odds of CWD infection with each 1-percent increase in soil clay content within its approximate home range in north-central Colorado. These results suggest that some regions may have a greater probability of maintaining and spreading CWD based solely on their geologic and chemical attributes. Thus, the soil characteristics within an animal’s range represent a potentially important spatial risk factor for CWD occurrence and maintenance.
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Lastly, other confounding risk factors may exist that play a role in CWD spatial dynamics. Sources of potential CWD exposure not related to natural movements of live, free-ranging animals could confound interpretation of spatial distribution and changes therein. Consequently, the occurrence and distribution of other potential risk factors (for example, game farms, taxidermy operations, wildlife rehabilitation activities, artificial baiting or feeding sites, depots for carcasses of vehicle-killed cervids) should be taken into account when designing monitoring plans.
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Several factors need to be considered when proposing to discontinue disease surveillance in addition to assumptions of the above model. First, what is the risk of an infected individual entering the study area through immigration of free-ranging animals from known or unknown positive jurisdictions or movement of captive cervids? If this risk is greater than zero, decisions on whether or not to continue to conduct surveillance should carefully weigh the level of this risk, because ultimately some chance exists of introduction of the disease. Secondly, agencies need to consider if they have adequate spatial coverage of sampling units across the jurisdiction to ensure all potential pockets of disease are sampled, and if they have effectively sampled individual animals within sampling units. Third, agencies need to consider the social and political repercussions of stopping surveillance activities. Lastly, availability of resources will play perhaps the most important role in determining whether surveillance should proceed or not. A cautionary tale against stopping surveillance too soon is provided by past CWD developments in Michigan. CWD surveillance in Michigan had continued since 1998 with 23,739 white-tailed deer, 887 elk, and 46 moose tested as of October 21, 2008 (Daniel O’Brien, Michigan Department of Natural Resources, oral commun). In addition, 8,452 captive cervids have been tested by the Michigan Department of Agriculture. Even with 10 years of surveillance effort, the first positive case was discovered in a captive animal in fall of 2008. Thus, even with a reasonable level of surveillance effort for a considerable period of time, a new case may be detected where a jurisdiction was previously believed to be CWD-free when the probability of introduction is greater than zero.
http://pubs.usgs.gov/of/2012/1036/pdf/ofr2012_1036.pdf
*** 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.
(PLEASE NOTE SOME OF THESE OLD UK GOVERNMENT FILE URLS ARE SLOW TO OPEN, AND SOMETIMES YOU MAY HAVE TO CLICK ON MULTIPLE TIMES, PLEASE BE PATIENT, ANY PROBLEMS PLEASE WRITE ME PRIVATELY, AND I WILL TRY AND FIX OR SEND YOU OLD PDF FILE...TSS)
http://collections.europarchive.org/tna/20080102193705/http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf
2011
Wednesday, October 12, 2011
White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation
It is unlikely that CWD will be eradicated from free-ranging cervids, and the disease is likely to continue to spread geographically [10]. However, the potential that 17 white-tailed deer may be susceptible to sheep scrapie by a natural route presents an additional confounding factor to halting the spread of CWD. This leads to the additional speculations that 1) infected deer could serve as a reservoir to infect sheep with scrapie offering challenges to scrapie eradication efforts and 2) CWD spread need not remain geographically confined to current endemic areas, but could occur anywhere that sheep with scrapie and susceptible cervids cohabitate.
This work demonstrates for the first time that white-tailed deer are susceptible to sheep scrapie by intracerebral inoculation with a high attack rate and that the disease that results has similarities to CWD. These experiments will be repeated with a more natural route of inoculation to determine the likelihood of the potential transmission of sheep scrapie to white-tailed deer. If scrapie were to occur in white-tailed deer, results of this study indicate that it would be detected as a TSE, but may be difficult to differentiate from CWD without in-depth biochemical analysis.
Author: Justin GreenleeJodi SmithRobert Kunkle Credits/Source: Veterinary Research 2011, 42:107
http://www.veterinaryresearch.org/content/pdf/1297-9716-42-107.pdf
http://chronic-wasting-disease.blogspot.com/2011/10/white-tailed-deer-are-susceptible-to.html
PPo3-22:
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.
http://www.prion2010.org/bilder/prion_2010_program_latest_w_posters_4_.pdf?139&PHPSESSID=a30a38202cfec579000b77af81be3099
Wednesday, September 08, 2010
CWD PRION CONGRESS SEPTEMBER 8-11 2010
http://chronic-wasting-disease.blogspot.com/2010/09/cwd-prion-2010.html
P35
ADAPTATION OF CHRONIC WASTING DISEASE (CWD) INTO HAMSTERS, EVIDENCE OF A WISCONSIN STRAIN OF CWD
Chad Johnson1, Judd Aiken2,3,4 and Debbie McKenzie4,5 1 Department of Comparative Biosciences, University of Wisconsin, Madison WI, USA 53706 2 Department of Agriculture, Food and Nutritional Sciences, 3 Alberta Veterinary Research Institute, 4.Center for Prions and Protein Folding Diseases, 5 Department of Biological Sciences, University of Alberta, Edmonton AB, Canada T6G 2P5 The identification and characterization of prion strains is increasingly important for the diagnosis and biological definition of these infectious pathogens. Although well-established in scrapie and, more recently, in BSE, comparatively little is known about the possibility of prion strains in chronic wasting disease (CWD), a disease affecting free ranging and captive cervids, primarily in North America. We have identified prion protein variants in the white-tailed deer population and demonstrated that Prnp genotype affects the susceptibility/disease progression of white-tailed deer to CWD agent. The existence of cervid prion protein variants raises the likelihood of distinct CWD strains. Small rodent models are a useful means of identifying prion strains. We intracerebrally inoculated hamsters with brain homogenates and phosphotungstate concentrated preparations from CWD positive hunter-harvested (Wisconsin CWD endemic area) and experimentally infected deer of known Prnp genotypes. These transmission studies resulted in clinical presentation in primary passage of concentrated CWD prions. Subclinical infection was established with the other primary passages based on the detection of PrPCWD in the brains of hamsters and the successful disease transmission upon second passage. Second and third passage data, when compared to transmission studies using different CWD inocula (Raymond et al., 2007) indicate that the CWD agent present in the Wisconsin white-tailed deer population is different than the strain(s) present in elk, mule-deer and white-tailed deer from the western United States endemic region
http://www.istitutoveneto.it/prion_09/Abstracts_09.pdf
Thursday, February 17, 2011
Environmental Sources of Scrapie Prions
http://scrapie-usa.blogspot.com/2011/02/environmental-sources-of-scrapie-prions.html
Thursday, June 09, 2011
Detection of CWD prions in salivary, urinary, and intestinal tissues of deer: potential mechanisms of prion shedding and transmission
http://chronic-wasting-disease.blogspot.com/2011/06/detection-of-cwd-prions-in-salivary.html
Chemosphere. 2012 Jan 20. [Epub ahead of print]
Soil-mediated prion transmission: Is local soil-type a key determinant of prion disease incidence?
Saunders SE, Bartz JC, Bartelt-Hunt SL.
Source
Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, NE 68182, USA.
Abstract
Prion diseases, including chronic wasting disease (CWD) and scrapie, can be transmitted via indirect environmental routes. Animals habitually ingest soil, and results from laboratory experiments demonstrate prions can bind to a wide range of soils and soil minerals, retain the ability to replicate, and remain infectious, indicating soil could serve as a reservoir for natural prion transmission and a potential prion exposure route for humans. Preliminary epidemiological modeling suggests soil texture may influence the incidence of prion disease. These results are supported by experimental work demonstrating variance in prion interactions with soil, including variance in prion soil adsorption and soil-bound prion replication with respect to soil type. Thus, local soil type may be a key determinant of prion incidence. Further experimental and epidemiological work is required to fully elucidate the dynamics of soil-mediated prion transmission, an effort that should lead to effective disease management and mitigation strategies.
Copyright © 2012 Elsevier Ltd. All rights reserved.
http://www.sciencedirect.com/science/article/pii/S0045653512000057
see much more on soil here ;
Survival and Limited Spread of TSE Infectivity after Burial
Karen Fernie, Allister Smith and Robert A. Somerville The Roslin Institute and R(D)SVS; University of Edinburgh; Roslin, Scotland UK
Scrapie and chronic wasting disease probably spread via environmental routes, and there are also concerns about BSE infection remaining in the environment after carcass burial or waste 3disposal. In two demonstration experiments we are determining survival and migration of TSE infectivity when buried for up to five years, as an uncontained point source or within bovine heads. Firstly boluses of TSE infected mouse brain were buried in lysimeters containing either sandy or clay soil. Migration from the boluses is being assessed from soil cores taken over time. With the exception of a very small amount of infectivity found 25 cm from the bolus in sandy soil after 12 months, no other infectivity has been detected up to three years. Secondly, ten bovine heads were spiked with TSE infected mouse brain and buried in the two soil types. Pairs of heads have been exhumed annually and assessed for infectivity within and around them. After one year and after two years, infectivity was detected in most intracranial samples and in some of the soil samples taken from immediately surrounding the heads. The infectivity assays for the samples in and around the heads exhumed at years three and four are underway. These data show that TSE infectivity can survive burial for long periods but migrates slowly. Risk assessments should take into account the likely long survival rate when infected material has been buried. The authors gratefully acknowledge funding from DEFRA.
SNIP...SEE FULL TEXT ;
http://chronic-wasting-disease.blogspot.com/2011/12/chronic-wasting-disease-cwd-wisconsin.html
Friday, February 03, 2012
Wisconsin Farm-Raised Deer Farms and CWD there from 2012 report Singeltary et al
http://chronic-wasting-disease.blogspot.com/2012/02/wisconsin-farm-raised-deer-farms-and.html
Thursday, February 09, 2012
Colorado Farm-Raised Deer Farms and CWD there from 2012 report Singeltary et al
http://chronic-wasting-disease.blogspot.com/2012/02/colorado-farm-raised-deer-farms-and-cwd.html
Monday, February 13, 2012
Stop White-tailed Deer Farming from Destroying Tennessee’s Priceless Wild Deer Herd oppose HB3164
http://chronic-wasting-disease.blogspot.com/2012/02/stop-white-tailed-deer-farming-from.html
Tuesday, February 14, 2012
Oppose Indiana House Bill 1265 game farming cervids
http://chronic-wasting-disease.blogspot.com/2012/02/oppose-indiana-house-bill-1265-game.html
Wednesday, February 15, 2012
West Virginia Deer Farming Bill backed by deer farmers advances, why ? BE WARNED CWD
http://chronic-wasting-disease.blogspot.com/2012/02/west-virginia-deer-farming-bill-backed.html
Monday, November 14, 2011
WYOMING Creutzfeldt Jakob Disease, CWD, TSE, PRION REPORTING 2011
http://transmissiblespongiformencephalopathy.blogspot.com/2011/11/wyoming-creutzfeldt-jakob-disease-cwd.html
http://gf.state.wy.us/web2011/wildlife-1000288.aspx
http://gf.state.wy.us/services/news/pressreleases/index.asp
CWD WISCONSIN
http://dnr.wi.gov/news/
http://dnr.wi.gov/org/land/wildlife/hunt/regs/bait.htm
Chronic Wasting Disease and the Science in support of the Ban on Baiting and Feeding Deer.
Timothy R. Van Deelen Ph.D. Wisconsin DNR Research
http://dnr.wi.gov/org/land/wildlife/Whealth/issues/Cwd/doc/cwdscsu.pdf
http://search.dnr.wi.gov/search?q=cwd&btnG=DNR+Search&client=DNR_frontend&output=xml_no_dtd&proxystylesheet=DNR_frontend&getfields=*&entqr=0&oe=UTF-8&ie=UTF-8&ud=1&sort=date%3AD%3AS%3Ad1&site=default_collection
2011 Law Enforcement deer gun season report
ILLEGAL BAITING AND FEEDING OF DEER
Across the state, baiting and feeding complaints and arrests were down significantly. Hotline complaints regarding illegal baiting and feeding were down 5% from 2010 and 50% from 2009. Arrests for illegal baiting were down 15%, and arrests for illegal feeding were down 13% from 2010 numbers.
http://dnr.wi.gov/org/es/enforcement/docs/2011%20le%20deer%20season%20report%20(web%20version).pdf
Wednesday, November 16, 2011
Wisconsin Creutzfeldt Jakob Disease, CWD, TSE, PRION REPORTING 2011
http://transmissiblespongiformencephalopathy.blogspot.com/2011/11/wisconsin-creutzfeldt-jakob-disease-cwd.html
Sunday, November 13, 2011
COLORADO CWD CJD TSE PRION REPORTING 2011
http://transmissiblespongiformencephalopathy.blogspot.com/2011/11/colorado-cwd-cjd-tse-prion-reporting.html
PLUS, THE CDC DID NOT PUT THIS WARNING OUT FOR THE WELL BEING OF THE DEER AND ELK ;
Thursday, May 26, 2011
Travel History, Hunting, and Venison Consumption Related to Prion Disease Exposure, 2006-2007 FoodNet Population Survey
Journal of the American Dietetic Association Volume 111, Issue 6 , Pages 858-863, June 2011.
http://transmissiblespongiformencephalopathy.blogspot.com/2011/05/travel-history-hunting-and-venison.html
NOR IS THE FDA recalling this CWD positive elk meat for the well being of the dead elk ;
Wednesday, March 18, 2009
Noah's Ark Holding, LLC, Dawson, MN RECALL Elk products contain meat derived from an elk confirmed to have CWD NV, CA, TX, CO, NY, UT, FL, OK RECALLS AND FIELD CORRECTIONS: FOODS CLASS II
http://chronic-wasting-disease.blogspot.com/2009/03/noahs-ark-holding-llc-dawson-mn-recall.html
kind regards, terry
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