Chronic Wasting Disease

Since its initial identification in Colorado in captive mule deer in the late 1960s and free-ranging elk in the 1980s, chronic wasting disease (CWD) has affected captive and free-ranging cervids (members of the deer family) in about half the States in the United States, as well as Canada, South Korea, Norway, Finland, and Sweden, and continues to spread across North America through new and recurring outbreaks. The only prion disease known to affect free-ranging wildlife, CWD is increasing in prevalence in areas where the disease is already established. In heavily affected areas of Wyoming, Colorado, and Wisconsin, more than 40% of free-ranging cervids are infected; wildlife managers and researchers have documented CWD-associated population declines in white-tailed deer, mule deer, and elk.

CWD is one member of a family of diseases called transmissible spongiform encephalopathies (TSEs), which includes scrapie in sheep and goats, bovine spongiform encephalopathy (commonly called “mad cow disease”) in cattle, and Creutzfeldt Jakob disease in humans. The causative agents of TSEs are thought to be prions. Prions are unconventional pathogenic agents that are comprised mostly, if not entirely, of an abnormal, infectious form of a normally occurring host protein called a prion protein. Prion proteins are found most abundantly in mammalian brain and central nervous system tissues. Currently, effective treatment for CWD does not exist, and management practices to prevent disease transmission in cervids are limited.

Scientists at the USGS National Wildlife Health Center (NWHC) work collaboratively with and provide technical assistance to various federal, state, and tribal natural resources agencies, academic institutions, nongovernmental organizations and industry partners. Some of these collaborative efforts include, but are not limited to: 

1. Understanding the biology, ecology, and epidemiology of CWD
2. Assessing and predicting the spread and persistence of CWD in wildlife and the environment; and
3. Developing tools for early detection, diagnosis, surveillance, and control of CWD.

Research performed at the NWHC has been instrumental in developing surveillance strategies for early detection of CWD in Montana (Montana Fish, Wildlife and Parks Department) and Shenandoah National Park (National Park Service), identifying potential disease risks posed by CWD to noncervid species such as bighorn sheep, and identifying environmental factors, like soil and plants, that may facilitate CWD transmission on the landscape.

The benefits of USGS research on CWD extend beyond wildlife management. For example, USGS scientists identified a novel enzyme from lichens with the ability to break down infectious prion protein that is being studied for its use in decontaminating human hospital environments in collaboration with an industry partner. Efforts will continue to focus on improving diagnostic testing platforms in collaboration with the U.S. Food and Drug Administration, providing surveillance and modeling technical assistance to a long-term CWD study carried out by the Wisconsin Department of Natural Resources, developing modeling techniques for predicting CWD growth within free-ranging cervid populations and forecasting disease spread in regions of interest, and continued identification and development of novel anti-prion compounds and processes to disrupt disease transmission cycles.

In addition to research, the NWHC also conducts numerous communications and outreach activities and products, such as fact sheets, briefings, media interviews, and presentations, on both a national and international scale. 

To learn more about Chronic Wasting Disease, see our fact sheet - Chronic Wasting Disease: Status, Science, and Management Support by the U.S. Geological Survey. 

To learn more about the plan for assisting states, federal agencies, and tribes in managing chronic wasting disease in wild and captive cervids, see - Federal Plan for Assisting States, Federal Agencies, and Tribes 2002. 

Access up-to-date maps of the expanding distribution of chronic wasting disease.