Prions, those misfolded proteins associated with diseases such as bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in cervids and Creutzfeldt-Jakob disease (CJD) in humans, are tough little molecules. Unlike food-borne pathogens, prions are generally not damaged by the heat of cooking, and, in the case of CWD, the prions infected animals shed into the environment can persist on plants or in the soil for months or even years. Scientists have found evidence that CWD can spread among wild or captive cervid populations through indirect contact, such as on forage contaminated with the saliva of infected animals.
Mark Zabel, PhD, leads the Prion Research Center at Colorado State University’s College of Veterinary Medicine and Biomedical Sciences. He and graduate student Aimee Ortega recently published a review titled “The Ecology of Prions” in Microbiology and Molecular Biology Reviews, outlining current understanding of prions in the environment and some possible measures for reducing their transmission between animals.
In the review, Zabel and Ortega note that animals infected with CWD can shed large volumes of prions in their saliva, urine and feces, and the decomposing remains of animals that die from the disease also release prions that persist in the environment. Where deer or elk concentrate around feed sources, or repeatedly return to the same feeding areas, the likelihood of indirect contact through ingestion of contaminated plants increases.
Zabel and his team theorize that controlled burning in selected areas could reduce that exposure and CWD transmission. Interestingly, the heat from a grass fire probably is not sufficient to destroy all the prions, but strategic burning could remove contaminated forage and reduce the chance of animals ingesting the prions. The CSU team plans to conduct field tests to evaluate controlled burning as a tool for reducing the spread of CWD in deer and elk herds.