The Department of Natural Resources (DNR) has planned two special deer hunts this month aimed at limiting the spread of chronic wasting disease (CWD). The two hunts are planned for areas south of Interstate 90 in southeastern Minnesota where residents and non-residents can hunt with a permit from December 21-23 and December 28-30. According to the DNR, reducing deer numbers will help to removed infected animals from this area. As of March 2018, CWD was detected in Olmsted, Fillmore, and Winona counties (Chronic Wasting Disease Alliance, 2018).
What is CWD and why does it matter? CWD is an incurable neurodegenerative (hence ‘wasting’) fatal disease that affects populations of deer, elk, and moose. Particularly this has affected populations in North America, South Korea, Sweden, and Norway (Kuznetsova, et al., 2018). The nature of the disease allows for proteins to stay within rotting carcasses, feces, or saliva of the infected animals which can seep into the soil. When a deer grazes in these areas, the infection is easily spread from the prions (misfolded protein). The concern for CWD ultimately stems from public and agency concerns about human health risks. The World Health Organization has recommended keeping all known prion diseases from entering the human food chain out of safety concern (CDC, 2018).
However, there may also be another tactic within reach for the management of CWD. Enter soil mineralogy. Previous studies have shown that prions are influenced by the soil mineralogy because they are easily bonded to quartz, kaolinite, and montmorillonite (Kuznetsova, 2018). Humic acid, a group of molecules that bind to and help plant roots receive water and nutrients, affect prions in a way that can change future CWD management. A study in which researchers injected mice with a mixture of humic acid and CWD infected elk brain tissue suggested that the mice with higher doses of the humic acid produced weaker prion signals. The humic acid had degraded the prions. Additionally, almost half the infected cases of mice did not show any symptoms of CWD within 280 days!
Having this knowledge, it can be derived that humic acid can assist efforts in limiting CWD’s spread that could essentially “disinfect” farmland. The DNR and other scientists could use this information to identify what areas may be more susceptible to prion transmission based upon the humic acid content of the soil. This could also be seen as a benefit to farmers as humic acid can dramatically increase yields of crops. As always, future studies are needed to help solidify this research and possible future management outcomes. With this knowledge, CWD could be something we see less of if wildlife managers can encourage the science behind it all.
Centers for Disease Control and Prevention. (2018 October 9). Chronic Wasting Disease (CWD). Retrieved from https://www.cdc.gov/prions/cwd/index.html
Chronic Wasting Disease Alliance. (2018). Minnesota CWD Information. Retrived from http://cwd-info.org/category/minnesota/
Kuznetsova, A., Cullingham, C., McKenzie, D., & Aiken, J. (2018). Soil humic acids degrade CWD prions and reduce infectivity. PLOS Pathogens, 14(11), e1007414. https://doi.org/10.1371/journal.ppat.1007414