Chronic wasting disease (CWD) of the deer family is a member of a group of infectious diseases caused by transmissible proteins called prions. Similar diseases include scrapie in sheep and goats, bovine spongiform encephalopathy in cattle ("mad cow disease"), and Creutzfeldt-Jacob disease in humans. In all of these diseases, prion proteins accumulate in the brain of affected individuals, causing neural degeneration and inevitably, death. The only place in the world where these diseases are known to occur in free-ranging wildlife is in northeastern Colorado and southeastern Wyoming, where an epidemic of CWD has been ongoing in populations of mule deer and elk for at least two decades. Our project will study this epidemic to better understand how CWD is transmitted, to develop mathematical models predicting its spread, and to evaluate ways to contain the disease. Mice that have been genetically engineered for susceptibility to CWD will be used to investigate how the disease is transmitted, and particularly to discover if it can be transmitted from animal residues that accumulate in the environment (urine, feces, saliva, and carcasses). Competing mathematical models portraying the spread of the disease will be developed. The predictions of these models will be compared with field data on disease prevalence to identify the model that most reliably represents the behavior of the disease in mule deer populations. This model will be analyzed to understand how changes in land use resulting from rapid development are likely to affect the dynamics of the disease and to evaluate strategies for its management.

Chronic wasting disease poses a potentially catastrophic threat to members of the deer family throughout Western North America. Expansion of the current epidemic could reduce the abundance and distribution of deer and elk throughout the region and, in so doing, could cause enduring harm to recreation-based economies of the West. Moreover, although direct threats of this disease to human health have not been established, they have not be ruled out. CWD is currently localized, but similar diseases affect animals and people worldwide. It follows that limiting the spread of CWD represents a fundamentally important challenge for protecting the health of natural and human dominated ecosystems throughout the region, and, in the fullness of time, throughout the world. Our research will contribute the understanding needed to develop effective strategies for combating this potentially devastating disease.