Project overview
Chronic Wasting Disease (CWD) is a fatal neurodegenerative disease affecting cervids, such as deer, elk, and moose. CWD is caused by infectious prions, which are highly stable misfolded proteins that can remain infectious in soils for at least 16 years. CWD has become widespread among cervids in Minnesota over the past few years, and there are increased concerns about transmission to humans through consumption of contaminated meat. CWD prions have been detected in Minnesota soils and surface waters near infected deer carcasses, indicating potential risk of environmental exposure. Additionally, prions in waterways may be transported hydrologically, widening the potential range of the disease. While the spread of CWD has primarily been studied via animal transmission, it is crucial to predict how prions are transported through the environment in order to effectively contain the disease.
The hydrological transport of prions is under-characterized, though we have observed that prions readily associate with fine sediments in surface waters. In order to predict rates of prion transport downstream from contaminated areas, we aim to characterize fine sediment transport dynamics in diverse Minnesota watersheds. Specifically, we will consider intermittent flow in drainage ditches adjacent to farms, as contaminated cervid farms are linked to several CWD outbreaks. During periods of no flow, sediment deposits in ditches can store CWD prions. Sediment-bound prions can be mobilized during flow caused by precipitation or snowmelt and then transported downstream.
Our objective is to determine the critical shear stress required to mobilize fine sediments through flume experiments. Are circulating flume will be packed with sediments and filled with water containing varying dissolved organic matter concentrations to represent the respective conditions of contaminated sites in north central and southeast Minnesota. Using particle image velocimetry, we will measure parameters to calculate critical shear stress of fines under different bed and water compositions.