Assessment of Chronic Wasting Disease Prion Shedding in Deer Saliva with Occupancy Modeling

Assessment of Chronic Wasting Disease Prion Shedding in Deer Saliva with Occupancy Modeling

1. Kristen A. Davenport^a, 
2. Brittany A. Mosher^b, 
3. Brian M. Brost^c,
4. Davin M. Henderson^a, 
5. Nathaniel D. Denkers^a, 
6. Amy V. Nalls^a, 
7. Erin McNulty^a,
8. Candace K. Mathiason^a and 
9. Edward A. Hoover^a

1. aPrion Research Center, Microbiology, Immunology and Pathology Department, Colorado State University, Fort Collins, Colorado, USA
2. bFish, Wildlife and Conservation Biology Department, Colorado State University, Fort Collins, Colorado, USA
3. cMarine Mammal Laboratory, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington, USA

1. Brad Fenwick, Editor

+Author Affiliations

1. University of Tennessee at Knoxville

ABSTRACT

The detection of prions is difficult due to the peculiarity of the pathogen, which is a misfolded form of a normal protein. The specificity and sensitivity of detection methods are imperfect in complex samples, including in excreta. Here, we combined optimized prion amplification procedures with a statistical method that accounts for false-positive and false-negative errors to test deer saliva for chronic wasting disease (CWD) prions. This approach enabled us to discriminate the shedding of prions in saliva and the detection of prions in saliva—a distinction crucial to understanding the role of prion shedding in disease transmission and for diagnosis. We found that assay sensitivity and specificity were indeed imperfect, and we were able to draw several conclusions pertinent to CWD biology from our analyses: (i) the shedding of prions in saliva increases with time postinoculation, but is common throughout the preclinical phase of disease; (ii) the shedding propensity is influenced neither by sex nor by prion protein genotype at codon 96; and (iii) the source of prion-containing inoculum used to infect deer affects the likelihood of prion shedding in saliva; oral inoculation of deer with CWD-positive saliva resulted in 2.77 times the likelihood of prion shedding in saliva compared to that from inoculation with CWD-positive brain. These results are pertinent to horizontal CWD transmission in wild cervids. Moreover, the approach described is applicable to other diagnostic assays with imperfect detection.

KEYWORDS

• CWD
 
• RT-QuIC
 
• false negative
 
• false positive
 
• occupancy modeling
 
• prion

FOOTNOTES

• Received 3 August 2017.
• Returned for modification 1 September 2017.
• Accepted 31 October 2017.
• Accepted manuscript posted online 8 November 2017.
• Address correspondence to Edward A. Hoover, edward.hoover@colostate.edu.
• Citation Davenport KA, Mosher BA, Brost BM, Henderson DM, Denkers ND, Nalls AV, McNulty E, Mathiason CK, Hoover EA. 2018. Assessment of chronic wasting disease prion shedding in deer saliva with occupancy modeling. J Clin Microbiol 56:e01243-17. https://doi.org/10.1128/JCM.01243-17.
• Supplemental material for this article may be found at https://doi.org/10.1128/JCM.01243-17.

• Copyright © 2017 American Society for Microbiology.

All Rights Reserved.

http://jcm.asm.org/content/56/1/e01243-17.abstract

Volume 23, Number 9—September 2017 

Research Letter Chronic Wasting Disease Prion Strain Emergence and Host Range Expansion

***Thus, emergent CWD prion strains may have higher zoonotic potential than common strains.

https://wwwnc.cdc.gov/eid/article/23/9/16-1474_article

2017

Subject: ***CDC Now Recommends Strongly consider having the deer or elk tested for CWD before you eat the meat

CDC Now Recommends Strongly consider having the deer or elk tested for CWD before you eat the meat 

Chronic Wasting Disease (CWD) 

Prevention 

* Strongly consider having the deer or elk tested for CWD before you eat the meat. 

* If you have your deer or elk commercially processed, consider asking that your animal be processed individually to avoid mixing meat from multiple animals. 

* If your animal tests positive for CWD, do not eat meat from that animal. 

https://www.cdc.gov/prions/cwd/prevention.html

 > 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).*** 

http://www.tandfonline.com/doi/full/10.4161/pri.28124?src=recsys

http://www.tandfonline.com/doi/pdf/10.4161/pri.28124?needAccess=true

http://wwwnc.cdc.gov/eid/article/20/1/13-0858_article.htm

TUESDAY, SEPTEMBER 12, 2017 

CDC Now Recommends Strongly consider having the deer or elk tested for CWD before you eat the meat 

http://chronic-wasting-disease.blogspot.com/2017/09/cdc-now-recommends-strongly-consider.html

SATURDAY, JANUARY 27, 2018 

CDC CHRONIC WASTING DISEASE CWD TSE PRION UPDATE REPORT USA JANUARY 2018

http://chronic-wasting-disease.blogspot.com/2018/01/cdc-chronic-wasting-disease-cwd-tse.html

kind regards, terry