Sunday, March 29, 2020

Can genetic assignment tests provide insight on the influence of captive egression on the epizootiology of chronic wasting disease?

Evol Appl. 2019 Dec 9;13(4):715-726. doi: 10.1111/eva.12895. eCollection 2020 Apr.

Can genetic assignment tests provide insight on the influence of captive egression on the epizootiology of chronic wasting disease?

Author information


Identifying the sources of ongoing and novel disease outbreaks is critical for understanding the diffusion of epizootic diseases. Identifying infection sources is difficult when few physical differences separate individuals with different origins. Genetic assignment procedures show great promise for assessing transmission dynamics in such situations. Here, we use genetic assignment tests to determine the source of chronic wasting disease infections in free-ranging white-tailed deer (Odocoileus virginianus) populations. Natural dispersal is thought to facilitate the geographic diffusion of chronic wasting disease, but egression from captive cervid populations represents an alternative source of infection that is difficult to detect due to physical similarities with wild deer. Simulated reference populations were created based on allele frequencies from 1,912 empirical microsatellite genotypes collected in four sampling subregions and five captive facilities. These reference populations were used to assess the likelihood of ancestry and assignment of 1,861 free-ranging deer (1,834 noninfected and 27 infected) and 51 captive individuals to captive or wild populations. The ancestry (Q) and assignment scores (A) for free-ranging deer to wild populations were high (average Q wild = 0.913 and average A wild = 0.951, respectively), but varied among subregions (Q wild = 0.800-0.947, A wild = 0.857-0.976). These findings suggest that captive egression and admixture are rare, but risk may not be spatially uniform. Ancestry and assignment scores for two free-ranging deer with chronic wasting disease sampled in an area where chronic wasting disease was previously unobserved in free-ranging herds indicated a higher likelihood of assignment and proportion of ancestry attributable to captive populations. While we cannot directly assign these individuals to infected facilities, these findings suggest that rare egression events may influence the epizootiology of chronic wasting disease in free-ranging populations. Continued disease surveillance and genetic analyses may further elucidate the relative disease risk attributable to captive and wild sources.
© 2019 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.


Odocoileus virginianus; admixture; captive egression; chronic wasting disease; genetic assignment tests

TEXAS BREEDER DEER ESCAPEE WITH CWD IN THE WILD, or so the genetics would show?

OH NO, please tell me i heard this wrong, a potential Texas captive escapee with cwd in the wild, in an area with positive captive cwd herd?

apparently, no ID though. tell me it ain't so please...

23:00 minute mark

''Free Ranging Deer, Dr. Deyoung looked at Genetics of this free ranging deer and what he found was, that the genetics on this deer were more similar to captive deer, than the free ranging population, but he did not see a significant connection to any one captive facility that he analyzed, so we believe, Ahhhhhh, this animal had some captive ahhh, whatnot.''

Texas CWD TSE Prion 169 Positive To Date

Accurate Genomic Predictions for Chronic Wasting Disease in U.S. White-tailed Deer

Christopher M Seabury*1, David L Oldeschulte1, Eric K Bhattarai1, Dhruti Legare2, Pamela J
Ferro2, Richard P Metz3, Charles D Johnson3, Mitchell A. Lockwood4, Tracy A. Nichols5


Herein, we demonstrate that differential susceptibility to CWD and variation in natural disease progression are both heritable, polygenic traits in farmed U.S. WTD, and that genome-
wide SNP data can be used to produce accurate genomic predictions for risk (≥ 0.8167); thereby
providing the first novel strategy for reducing the prevalence of CWD. 

***>Moreover, given the genomic architecture of these traits, we also demonstrate that PRNP genotyping alone cannot be expected to facilitate an eradication program, or to rapidly reduce the overall prevalence of CWD in farmed U.S. WTD.


Dr. Mckenzie and CIDRAP on CWD TSE Prion

122: Prions and Chronic Wasting Disease with Jason Bartz

Texas CWD Symposium: Transmission by Saliva, Feces, Urine & Blood

the other part, these tissues and things in the body then shed or secrete prions which then are the route to other animals into the environment, so in particular, the things, the secretions that are infectious are salvia, feces, blood and urine. so pretty much anything that comes out of a deer is going to be infectious and potential for transmitting disease.

SUMMARY MINUTES OF THE 405th COMMISSION MEETING Texas Animal Health Commission December 10, 2019

Chronic Wasting Disease (CWD): Since July 2015, five positive captive breeder herds have been disclosed. Three herds were depopulated and two larger herds are managed with a herd plan. Two positive bucks were disclosed at one of the facilities in 2019. In addition, two positive free-ranging Mule Deer in El Paso County, one positive Mule Deer in Hartley County, and one positive freeranging WTD in Medina County were disclosed in 2019.

In Vitro detection of Chronic Wasting Disease (CWD) prions in semen and reproductive tissues of white tailed deer bucks (Odocoileus virginianus)
Carlos Kramm,Ruben Gomez-Gutierrez,Claudio Soto,Glenn Telling,Tracy Nichols,Rodrigo Morales Published: December 30, 2019
Chronic Wasting Disease (CWD) is a prion disease affecting several cervid species. Among them, white-tailed deer (WTD) are of relevance due to their value in farming and game hunting. The exact events involved in CWD transmission in captive and wild animals are still unclear. An unexplored mechanism of CWD spread involves transmissions through germplasm, such as semen. Surprisingly, the presence and load of CWD prions in semen and male sexual tissues from WTD has not been explored. Here, we described the detection of CWD prions in semen and sexual tissues of WTD bucks utilizing the Protein Misfolding Cyclic Amplification (PMCA) technology. Samples were obtained post-mortem from farmed pre-clinical, CWD positive WTD bucks possessing polymorphisms at position 96 of the PRNP gene. Our results show that overall CWD detection in these samples had a sensitivity of 59.3%, with a specificity of 97.2%. The data indicate that the presence of CWD prions in male sexual organs and fluids is prevalent in late stage, pre-clinical, CWD-infected WTD (80%-100% of the animals depending on the sample type analyzed). Our findings reveal the presence of CWD prions in semen and sexual tissues of prion infected WTD bucks. Future studies will be necessary to determine whether sexual contact and/or artificial inseminations are plausible means of CWD transmission in susceptible animal species.

Michigan CWD TSE Prion Total Suspect Positive Deer Moves Up To 188 with total deer tested 80,687 to date



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