A fatal illness with no vaccine: Chronic Wasting Disease
The disease affects white-tailed deer, mule deer, elk, and moose. Chronic wasting disease is contagious and has been detected in 26 states.
The U.S. Geological Survey is focused on the development of early detection and effective response tools that promote an adaptive management approach to chronic wasting disease.
Chronic wasting disease is not known to affect humans or livestock.
Chronic wasting disease is a fatal contagious neurological disease that affects free-ranging and captive cervids (members of the deer family) such as elk, moose, white-tailed deer, and mule deer.
Image: Elk, Melia DeVivo, Washington State Department of Natural Resources, with permission.
It is transmitted directly through animal-to-animal contact, and indirectly through contact with objects or an environment contaminated with infectious material such as saliva, urine, feces, and carcasses of chronic wasting disease-infected animals.
Chronic wasting disease, similar to scrapie in sheep and mad cow disease in cattle, is caused by prions. These pathogens mostly consist of an abnormal, infectious form of a host protein primarily found in the brain and central nervous system tissues of mammals.
Image: Wild cervids, Centers for Disease Control and Prevention.
Chronic wasting disease was initially identified in captive animals in the late 1960s and in free-ranging animals in the 1980s.
Since its initial identification in Colorado, chronic wasting disease continues to spread and has affected cervids in 26 States in the United States and 3 Provinces in Canada, as well as in Finland, Norway, South Korea, and Sweden.
Image: Elk infected with chronic wasting disease, National Park Service.
Scientists at the U.S. Geological Survey Wyoming Cooperative Fish and Wildlife Research Unit and their collaborators have documented chronic wasting disease-associated population declines in white-tailed deer and mule deer.
Image: White-tailed deer, Bureau of Land Management.
Importance of Cervids
Healthy cervid populations are critical to biodiversity. These species serve as a middle link in the food chain between the plants they eat and the predators that prey on them.
The effects of chronic wasting disease on these biologically, culturally, and economically valuable animals could be devastating if measures are not taken to prevent its spread and persistence in wildlife and the environment.
Cervids are a popular game species providing a valuable food source for many and considered Tribal cultural resources and traditional food sources across the United States (Great Lakes Indian Fish and Wildlife Commission, 2018).
Image credit: USGS.
According to the Outdoor Industry Association (2017), hunting and fishing contributed over $60 billion to U.S. retail spending in 2017, and sales of permits and licenses for hunting and fishing support State wildlife agency budgets.
Image: Outdoor Industry Association.
In 2016, 9.2 million hunters pursued big game such as deer and elk, with deer being the most popular attracting 8.1 million hunters across the U.S.
Deer were also among the most popular land mammals observed or photographed by 14 million people--according to the U.S. Fish and Wildlife Service and U.S. Census Bureau (2018).
Image: White-tailed deer, USGS.
Mapping the Spread of Chronic Wasting Disease
In areas of Colorado, Wisconsin, and Wyoming heavily affected by CWD, more than 40 percent of free-ranging cervids are infected.
Chronic wasting disease has been detected in 26 U.S. states and three Canadian provinces in free-ranging cervids and/or commercial captive cervid facilities.
Expanding Distribution of Chronic Wasting Disease map:
The USGS National Wildlife Health Center maintains an online map for North America that documents the expanding distribution of CWD. Map data orginate from State wildlife agencies, the U.S. Department of Agriculture, and the Canadian Food Inspection Agency and represent best-available information. This map is used and cited by Federal, State, and academic partners to monitor the spread of the disease.
U.S. Geological Survey Research: Early Detection Saves Valuable Time and Resources
The U.S. Geological Survey is instrumental in conducting risk assessments and developing chronic wasting disease surveillance strategies for early detection.
Weighted Surveillance for Detection of Chronic Wasting Disease
This application provides an easy-to-use interface for conducting weighted surveillance for chronic wasting disease in white-tailed deer populations. Weighted surveillance is based on the simple principle that within a population there exists heterogeneity among individuals with regard to disease risk.
In the Field
The U.S. Geological Survey Northern Prairie Wildlife Research Center is supporting National Park Service efforts to manage chronic wasting disease at Wind Cave National Park in South Dakota.
Past U.S. Geological Survey work found that chronic wasting disease was the leading cause of death in the park’s elk population with infection rates up to 24 percent.
Current efforts are focused on evaluating the effectiveness of reducing elk density on chronic wasting disease-related mortality in that population. Results will guide chronic wasting disease management at this and other national parks.
Image: Bull elk near Red Valley, within Wind Cave National Park, at sunrise. National Park Service.
Scientists at the U.S. Geological Survey Northern Rocky Mountain Science Center and the USGS Wyoming Cooperative Fish and Wildlife Research Unit work with the Wyoming Game and Fish Department to map the risk of chronic wasting disease spread from migrating mule deer to elk on feed grounds in western Wyoming.
Using movement data from Global Positioning System-collared elk and disease risk maps were developed for managers to focus surveillance.
Image: Mule deer migrations, Wyoming Migration Initiative.
USGS Scientists at the Pennsylvania Cooperative Research Unit are evaluating the effectiveness of targeted removal of white-tailed deer groups on chronic wasting disease occurrence and distribution.
Scientists are also implementing genetic research to understand the patterns of disease susceptibility and population connectivity across Maryland, Pennsylvania, and Virginia for targeted chronic wasting disease mitigation strategies.
Image: USGS lab technician prepares a DNA sample for genetic analysis.
Since 2002, chronic wasting disease prevalence in adult male white-tailed deer in western Wisconsin has increased to over 35 percent in 2019, from 8 to 10 percent (Wisconsin Department of Natural Resources, 2019).
Scientists at the U.S. Geological Survey National Wildlife Health Center, the Wisconsin Cooperative Wildlife Research Unit, and the Wisconsin Department of Natural Resources are developing a framework to understand relationships between CWD infection and deer demographic rates to guide management decisions.
Image: White-tailed deer, U.S. Fish and Wildlife Service.
In the Laboratory
Scientists at the USGS National Wildlife Health Center are working with experts in the medical industry to develop a process that optimizes the degradation of prions by existing or modified chemical solutions.
Image: White-tailed deer, U.S. Department of Agriculture Research Service.
Researchers have identified the temperature, pH, and process steps that provide the greatest reduction in prion infectivity.
Image: Testing prion contamination of plants, such as corn and other crops, to determine if they play a role in environmental prion transmission, source: Christina Carlson, USGS National Wildlife Health Center.
This work applies to prion decontamination for humans in hospitals as well as prion decontamination for animals in veterinary hospitals and at meat-processing facilities.
Image: Bull elk. National Park Service.
Prion-contaminated soil and plants, such as corn and other crops that deer feed on, may facilitate CWD transmission. Scientists at the USGS National Wildlife Health Center are working with those at the University of Wisconsin to study prion infectivity and prion uptake in plants to better understand what role crop plants play in transmission on the landscape.
Image: Mule deer trail camera photo, U.S. Geological Survey Northern Rocky Mountain Science Center.
USGS Podcast: Chronic Wasting Disease
References Cited
Chronic Wasting Disease-Research by the U.S. Geological Survey and Partners
U.S. Geological Survey Response to Chronic Wasting Disease
Chronic wasting disease—Status, science, and management support by the U.S. Geological Survey
Great Lakes IndianFish & Wildlife Commission
Expanding Distribution of Chronic Wasting Disease
CWD prevalence in Wisconsin
Distribution of Chronic Wasting Disease in North America
Contacts
Camille Hopkins, Wildlife Disease Coordinator, mchopkins@usgs.gov
Suzanna Soileau, Outreach Coordinator, ssoileau@usgs.gov
Dawn Childs, Information Specialist (story map development), dchilds@usgs.gov
For more information contact: Associate Director, Ecosystems, U.S. Geological Survey 12201 Sunrise Valley Drive, Mail Stop 300, Reston, VA
Cover image: White-tailed deer, U.S. Fish and Wildlife Service
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