Mineral licks as environmental reservoirs of chronic wasting disease prions

Abstract

Chronic wasting disease (CWD) is a fatal neurodegenerative disease of deer, elk, moose, and reindeer (cervids) caused by misfolded prion proteins. The disease has been reported across North America and recently discovered in northern Europe. Transmission of CWD in wild cervid populations can occur through environmental routes, but limited ability to detect prions in environmental samples has prevented the identification of potential transmission “hot spots”. We establish widespread CWD prion contamination of mineral licks used by free-ranging cervids in an enzootic area in Wisconsin, USA. We show mineral licks can serve as reservoirs of CWD prions and thus facilitate disease transmission. Furthermore, mineral licks attract livestock and other wildlife that also obtain mineral nutrients via soil and water consumption. Exposure to CWD prions at mineral licks provides potential for cross-species transmission to wildlife, domestic animals, and humans. Managing deer use of mineral licks warrants further consideration to help control outbreaks of CWD.

The ecology of chronic wasting disease in wildlife

“…in Wyoming) increase the risk of disease transmission (Creech et al, 2012). Similarly, recent detection of CWD PrP Sc in ecologically relevant environments, such as natural mineral licks where wildlife obtain minerals from soil and water consumption, suggests a key role of landscape features in CWD transmission risk (Plummer et al, 2018). Thus, identifying where and when CWD occurs in a timely fashion can help inform policies regarding baiting and supplemental feeding of cervids and to consider direct habitat modification with the aim of reducing infectious contact (Sorensen, van Beest & Brook, 2014).…”

“…For example, focal and consistent culling has been shown to reduce the prevalence of CWD in some wild cervid populations (Manjerovic et al, 2014;Sorensen et al, 2014), and simulations suggest that this approach can even eliminate the disease in certain situations (Potapov, Merrill & Lewis, 2012). This observation suggests that if CWD is discovered in high-value (endangered or conservation priority) isolated populations, where culling is not feasible, field testing and immediate culling of CWD-positive individuals could be economically and logistically feasible (Wolfe, Miller & Williams, 2004;Plummer et al, 2018). Combining theoretical approaches with surveillance data shows that deer density has varying levels of influence on contact rates and mechanisms of transmission (Storm et al, 2013;Potapov et al, 2013;Jennelle et al, 2014).…”

Update on chronic wasting disease (CWD) III

“…saliva) from another infected animal, or contact with body fluids, such as urine or faeces (NYSDEC, 2018). Artificial aggregation of deer: rearing animals in captivity, using urine lures for hunting purposes, feeding during the winter season and placing mineral salt licks in the field even if they are intended for the domestic species Sorensen et al, 2014;Plummer et al, 2018) NYSDEC (2018)…”

Long-Term Incubation PrPCWD with Soils Affects Prion Recovery but Not Infectivity

“…This study shows that although recovery of PrP CWD bound to soil minerals and whole soils with time become more difficult, prion infectivity is not significantly altered. Detection of prions in soil is, therefore, not only affected by soil type but also by length of time of the prion-soil interaction.Pathogens 2020, 9, 311 2 of 9 soils [12]. A number of laboratory studies have, however, suggested a time-dependent decline in the ability to detect rodent prions when bound to soils [22,25].…”

“…Pathogens 2020, 9, 311 2 of 9 soils [12]. A number of laboratory studies have, however, suggested a time-dependent decline in the ability to detect rodent prions when bound to soils [22,25].…”