October 6, 2015, a single shot echoed through the woods in Pruitt, Arkansas. A small, though seemingly healthy female elk collapsed far away from the herd. She was young, only two and a half years old, and upon further inspection appeared well on her way to emaciation. Her ribs protruded, straining against her thick hide, and abnormally thick saliva hung from her bony chin. Her starved appearance was far from all that was unusual about this kill. This young elk was separated from her herd, wandering in circles.
Several months later, on February 23, 2016, lab results would confirm the fears of hunters and conservationists alike; Chronic Wasting Disease had reached Arkansas.
Chronic Wasting Disease, or CWD is a neurodegenerative disease that effects the cervids, more specifically, mule deer, white-tailed deer, moose, and Rocky Mountain elk. The infectious agents are prions, or abnormally shaped proteins without their associated nucleic acids. These misshapen prions spur the development of porus, sponge-like lesions in brain tissue that lead to a deterioration in neurological function. CWD is unique in that it occurs in free-ranging species, as compared to Mad Cow disease, it’s rough, bovine equivalent that occurs only in domesticated species. Much is still unknown about this relatively new degenerative disease, and research is still required to discover the disease’s origins, as well as modeling the future of effected herds.
CWD has only been a known clinical syndrome for 30 years, though modeling suggest that it may have been present for over 40 years. It is conjectured that it may have originated from shared grazing areas with sheep, who fall victim to a similar neurodegenerative disease, scrapie, or it may have arisen spontaneously. CWD is particularly difficult to fight because it can spread through direct, animal to animal contact, or through saliva, feces, and other bodily secretions. The prions that cause infection are particularly stable, and can persist in the environment and contaminating grazing lands which makes CWD a particularly pernicious disease. Once infectious prions enter the environment, deer and elk that graze in the contaminated area become susceptible to infection. In small, contained grazing lands like those of the Ponca elk herd, this is especially problematic. The herd is dense and has a finite grazing area, and scientists are not sure how long the infectious agents may persist in the environment.