The Ecology of Prions

Abstract

Chronic wasting disease (CWD) affects cervids and is the only known prion disease readily transmitted among free-ranging wild animal populations in nature. The increasing spread and prevalence of CWD among cervid populations threaten the survival of deer and elk herds in North America, and potentially beyond. This review focuses on prion ecology, specifically that of CWD, and the current understanding of the role that the environment may play in disease propagation. We recount the discovery of CWD, discuss the role of the environment in indirect CWD transmission, and consider potentially relevant environmental reservoirs and vectors. We conclude by discussing how understanding the environmental persistence of CWD lends insight into transmission dynamics and potential management and mitigation strategies.

Keywords: cervids; chronic wasting disease; ecology; environment; plants; prions; soil; transmission; water.

FIG 1

CWD prion ecology. Shown is the potential movement of CWD prions in the environment. While direct transmission likely contributes the most to CWD spread, indirect transmission also occurs via CWD prion deposition into the environment from urine, feces, and saliva onto and into water, soil, and plants. Cervids and other animals likely consume prions contained in these reservoirs and become infected.