Chronic wasting disease (CWD) afflicts members of the deer family. Similar to diseases in sheep (scrapie) and cattle (bovine spongiform encephalopathy or "mad cow disease"), CWD is caused by misfolded proteins that resist breakdown by enzymes within cells. These proteins cause inevitably fatal, neurological damage. CWD poses grave threats to deer populations in North America and, in the fullness of time, throughout the world. Understanding and managing CWD depends on developing predictive models that represent how the disease spreads. The investigators will conduct field studies on wild populations of mule deer to develop models addressing three questions: 1) What is the mechanism of transmission? 2) How many susceptible individuals are infected by a single infected one? 3) How does an individual's genetic make-up interact with its exposure to CWD to determine its risk of infection? Animals will be captured and marked with radio transmitters to allow the investigators to recapture them at a later date. The disease status of marked individuals will be determined and samples will be taken from them for genetic analysis. Using methods based on histories of captures and the animals disease status at each capture, an individual's risk of infection will be estimated based on its genetics, movement patterns, and associations with other individuals. This project will support decisions on management of a disease that, left unchecked, is likely to cause grave harm to ecosystems and to rural economies. Broader impacts of the project include 1) innovative training of graduate students, 2) curriculum development and research experience for K-12 teachers, 3) outreach to citizens visiting Rocky Mountain National Park, 4) support for decisions on disease management by wildlife agencies in western North America, and 5) training for the research community in the modeling methods used by the project.