Chronic Wasting Disease

Chronic wasting disease (CWD) affects cervids (elk, moose, mule deer, and white-tailed deer) throughout the U.S. CWD affects the nervous system in these animals and creates distinctive brain lesions. At this time, we have no treatment for CWD and it is fatal to the animals who contract it.

CWD is caused by an infectious, irregular form of cellular prion protein. CWD can be directly and indirectly transmitted through the contact with saliva, urine, feces, and infected carcasses, or CWD contaminated environmental surfaces.

USGS scientists are studying CWD to determine how the disease is transmitted, whether sex and/or age of the animal play a role in infection, and whether a genetic resistance is present in some animals.

Cooperative Research

Chronic Wasting Disease — National Wildlife Health Center

Using host pathogen genetics to determine population connectivity — Northern Rocky Mountain Science Center

Modeling the implications of prion persistence in the environment on disease dynamics and deer populations — Northern Rocky Mountain Science Center

Estimating the force of infection from current-status data — Northern Rocky Mountain Science Center

CWD — USGS-Wisconsin Cooperative Wildlife Research Unit


Distribution of Chronic Wasting Disease in North America

  • Publications

  • Identifying priority chronic wasting disease surveillance areas for mule deer in Montana

    Chronic wasting disease (CWD) is a fatal prion disease that affects a variety of ungulate species including mule deer (Odocoileus hemionus). As of 2014, no CWD cases had been reported in free-ranging ungulates in Montana. However, nearby cases in Canada, Wyoming, and the Dakotas indicated that the disease was encroaching on Montana's borders. Mule deer are native and common throughout Montana, and they represent a significant portion of the total hunter-harvested cervids in the state. The arrival of CWD in Montana may have significant ecosystem and socioeconomic impacts as well as potential consequences for wildlife management. 

    The Journal of Wildlife Management, v. 79, June 2015

  • Assessing transmissible spongiform encephalopathy species barriers with an in vitro prion protein conversion assay

    Studies to understanding interspecies transmission of transmissible spongiform encephalopathies (TSEs, prion diseases) are challenging in that they typically rely upon lengthy and costly in vivo animal challenge studies. A number of in vitro assays have been developed to aid in measuring prion species barriers, thereby reducing animal use and providing quicker results than animal bioassays. Here, we present the protocol for a rapid in vitroprion conversion assay called the conversion efficiency ratio (CER) assay.

    J. Vis. Exp., v. 97, 2015

  • Using auxiliary information to improve wildlife disease surveillance when infected animals are not detected: a Bayesian approach

    There are numerous situations in which it is important to determine whether a particular disease of interest is present in a free-ranging wildlife population. However adequate disease surveillance can be labor-intensive and expensive and thus there is substantial motivation to conduct it as efficiently as possible. Surveillance is often based on the assumption of a simple random sample, but this can almost always be improved upon if there is auxiliary information available about disease risk factors. 

    PLoS ONE, v. 9, no. 3, March 2014