Prion Transmission among Texas Deer: A UTMB Collaboration with Texas Parks and Wildlife

Chronic wasting disease (CWD) was first discovered in Texas deer in 2012 (1). Since then cases have markedly increased, in part due to the CWD prion's wide transmissibility capacity. Chronic wasting disease can be spread between white-tailed deer via saliva, urine, feces and blood. Maternal-fetal transmission has also been documented. Fomite transmission is also a concern as prions can remain infectious in the environment for long periods of time (2). Once infected with CWD, deer only have about 18-24 months to live as the toll of weight loss, and neurologic symptoms gradually impacts the animals.

As a capable containment and biosecurity facility, UTMB was selected as the site of a novel study to answer this cross-species conundrum. Two white-tailed deer, one infected with CWD and one not, will be cohoused with Axis deer and regular sampling will be performed to assess transmission of the prion. The goal is to determine the risk of transmission between the species, which will influence regulations by Texas Parks and Wildlife meant to curb the statewide endemic of CWD. Currently, there is no evidence that CWD spreads to humans (4) and wildlife watchers need not have any concerns about contracting CWD. However, deer hunters are encouraged to get meat tested if they hunt in areas in Texas where deer are recognized to have CWD. Hunters are urged to not consume meat from a CWD positive animal as a precaution (4).

Taking a One Health perspective reveals that the CWD endemic could be causing multiple repercussions in the environment. As deer populations experience loss due to the endemic, the plants they consume could become overgrown, impacting other species. Further, it’s possible that animals that prey on deer or that eat deceased deer, like vultures, could become infected with CWD although further research needs to be performed to explore these concerns. Another research question of interest is whether or not ticks could spread CWD through infected bloodmeals, and are thus contributing to the spread of CWD. In addition, currently there is no good anti-mortem testing for CWD which inhibits our understanding of CWD incidence in Texas, although hunters are able to test their deer for CWD post-mortem. While many questions about CWD remain to be answered, we look forward to the upcoming results of the UTMB collaboration study as the loss of Texas deer and the repercussions this could have on biodiversity and ecological balance are saddening. As Dr. Lee eloquently put: “Go appreciate nature while we have it!”.

References:

1. Texas parks & wildlife department: Chronic wasting disease. (n.d.). Retrieved January 5, 2024, from https://tpwd.texas.gov/huntwild/wild/diseases/cwd/
2. Gough, K. C., & Maddison, B. C. (2010). Prion transmission. Prion, 4(4), 275–282. https://doi.org/10.4161/pri.4.4.13678
3. A species account of the axis deer (Axis axis) | mammals of texas | natural science research laboratory | ttu. (n.d.). Retrieved January 5, 2024, from https://www.depts.ttu.edu/nsrl/mammals-of-texas-online-edition/Accounts_Introduced_Artiodactyla/Axis_axis.php#:~:text=DISTRIBUTION.,HABITS.
4. Texas parks & wildlife department: General cwd faqs. (n.d.). Retrieved January 5, 2024, from https://tpwd.texas.gov/huntwild/wild/diseases/cwd/faqs.phtml#is-cwd-dangerous-humans.