The importance of localized culling in stabilizing chronic wasting disease prevalence in white-tailed deer populations, Preventive Veterinary Medicine (2013), http://dx.doi.org/10.1016/j.prevetmed.2013.09.011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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The importance of localized culling in stabilizing chronic wasting disease prevalence in white-tailed deer populations
Mary Beth Manjerovic1,2, Michelle L. Green1,2, Nohra Mateus-Pinilla1, and Jan Novakofski2
1Illinois Natural History Survey, University of Illinois Urbana-Champaign, 1816 S. Oak Street, Champaign, IL, 61820, USA
2Department of Animal Sciences, Illinois Natural History Survey, University of Illinois Urbana-Champaign, 1503 S. Maryland Drive, Urbana, IL, 61801, USA
Correspondence address: Illinois Natural History Survey University of Illinois Urbana-Champaign 1816 S. Oak Street Champaign, IL, 61820, USA firstname.lastname@example.org
Page 2 of 27 Accepted Manuscript
Strategies to contain the spread of disease often are developed with incomplete knowledge of the possible outcomes but are intended to minimize the risks associated with delaying control. Culling of game species by government agencies is one approach to control disease in wild populations but is unpopular with hunters and wildlife enthusiasts, politically unpalatable, and erodes public support for agencies responsible for wildlife management. We addressed the functional differences between hunting and government culling programs for managing chronic wasting disease (CWD) in white39 tailed deer by comparing prevalence over a 10-year period in Illinois and Wisconsin. We found similar prevalence in both states when management emphasized culling but an increase in CWD after Wisconsin switched from culling to a hunter-harvest focused management strategy. Despite its unpopularity among hunters, localized culling is a disease management strategy that can maintain low disease prevalence without affecting recreational deer harvest.
North American cervids [mule deer (Odocoileus hemionus), elk (Cervus elaphus), moose (Alces alces), and white-tailed deer (Odocoileus virginianus)] are popular game animals making them economically and recreationally valuable species. Free-living cervids are susceptible to chronic wasting disease (CWD) (Miller et al. 2000; Spraker et al. 1997), a contagious and fatal prion disease with no cure or treatment (Williams et al., 2002). To date, CWD has been identified in free-ranging cervid populations in 17 states and two Canadian provinces ( http://www.nwhc.usgs.gov/disease_information/chronic_wasting_disease/index.jsp) . CWD is spread in free-living animals through contact with bodily secretions or infectious agents persisting in contaminated environments (Mathiason et al., 2009, 2006; Walter et al., 2011; Williams et al., 2002). Such transmissibility results in a self-sustaining CWD epizootic with prevalence increasing slowly over time (Miller et al., 2000; Miller and Conner, 2005; Saunders et al., 2012; Williams et al., 2002). Furthermore, the environmental load of infectious prions increases with the number of infectious animals making CWD exceedingly difficult to eliminate from free-ranging populations once established (Almberg et al., 2011; Gross and Miller, 2001). CWD models suggest substantial declines in cervid populations with high prevalence and highlight the importance of long-term, sustained management programs in controlling CWD (Gross and Miller, 2001; Mateus-Pinilla et al., 2013; Wasserberg et al., 2009). ...
HD.13: CWD infection in the spleen of humanized transgenic mice
Liuting Qing and Qingzhong Kong
Case Western Reserve University; Cleveland, OH USA
Chronic wasting disease (CWD) is a widespread prion disease in free-ranging and captive cervid species in North America, and there is evidence suggesting the existence of multiple CWD strains. The susceptibility of human CNS and peripheral organs to the various CWD prion strains remains largely unclear. Current literature suggests that the classical CWD strain is unlikely to infect human brain, but the potential for peripheral infection by CWD in humans is unknown. We detected protease-resistant PrpSc in the spleens of a few humanized transgenic mice that were intracerebrally inoculated with natural CWD isolates, but PrpSc was not detected in the brains of any of the CWD-inoculated mice. Our ongoing bioassays in humanized Tg mice indicate that intracerebral challenge with such PrpSc-positive humanized mouse spleen already led to prion disease in most animals. ***These results indicate that the CWD prion may have the potential to infect human peripheral lymphoid tissues.
Oral.15: Molecular barriers to zoonotic prion transmission: Comparison of the ability of sheep, cattle and deer prion disease isolates to convert normal human prion protein to its pathological isoform in a cell-free system
Marcelo A.Barria,1 Aru Balachandran,2 Masanori Morita,3 Tetsuyuki Kitamoto,4 Rona Barron,5 Jean Manson,5 Richard Kniqht,1 James W. lronside1 and Mark W. Head1
1National CJD Research and Surveillance Unit; Centre for Clinical Brain Sciences; School of Clinical Sciences; The University of Edinburgh; Edinburgh, UK; 2National and OIE Reference Laboratory for Scrapie and CWD; Canadian Food Inspection Agency; Ottawa Laboratory; Fallowfield. ON Canada; 3Infectious Pathogen Research Section; Central Research Laboratory; Japan Blood Products Organization; Kobe, Japan; 4Department of Neurological Science; Tohoku University Graduate School of Medicine; Sendai. Japan; 5Neurobiology Division; The Roslin Institute and R(D)SVS; University of Edinburgh; Easter Bush; Midlothian; Edinburgh, UK
Background. Bovine spongiform encephalopathy (BSE) is a known zoonotic prion disease, resulting in variant Creurzfeldt- Jakob disease (vCJD) in humans. In contrast, classical scrapie in sheep is thought to offer little or no danger to human health. However, a widening range of prion diseases have been recognized in cattle, sheep and deer. The risks posed by individual animal prion diseases to human health cannot be determined a priori and are difficult to assess empirically. The fundamemal event in prion disease pathogenesis is thought to be the seeded conversion of normal prion protein (PrPC) to its pathological isoform (PrPSc). Here we report the use of a rapid molecular conversion assay to test whether brain specimens from different animal prion diseases are capable of seeding the conversion of human PrPC ro PrPSc.
Material and Methods. Classical BSE (C-type BSE), H-type BSE, L-type BSE, classical scrapie, atypical scrapie, chronic wasting disease and vCJD brain homogenates were tested for their ability to seed conversion of human PrPC to PrPSc in protein misfolding cyclic amplification (PMCA) reactions. Newly formed human PrPSc was detected by protease digestion and western blotting using the antibody 3F4.
Results. C-type BSE and vCJD were found to efficiently convert PrPC to PrPSc. Scrapie failed to convert human PrPC to PrPSc. Of the other animal prion diseases tested only chronic wasting disease appeared to have the capability ro convert human PrPC to PrPSc. The results were consistent whether the human PrPC came from human brain, humanised transgenic mouse brain or from cultured human cells and the effect was more pronounced for PrPC with methionine at codon 129 compared with that with valine.
Conclusion. Our results show that none of the tested animal prion disease isolates are as efficient as C-type BSE and vCJD in converting human prion protein in this in vitro assay. ***However, they also show that there is no absolute barrier ro conversion of human prion protein in the case of chronic wasting disease.
PRION2013 CONGRESSIONAL ABSTRACTS CWD
Sunday, August 25, 2013
***Chronic Wasting Disease CWD risk factors, humans, domestic cats, blood, and mother to offspring transmission
*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.