CWD Through the Years

Chronic wasting disease, an infectious prion disease of at least five cervid species, has run the gamut from minor scientific curiosity to national crisis since the syndrome’s first recognition in the late 1960s. Moving forward, we believe this wildlife disease merits attention somewhere between those extremes. Collective experiences and observations made over the last five decades can serve—for better or worse—as a solid foundation for wildlife and animal health professionals to build upon in addressing anticipated challenges posed by CWD in the decades to come. 

1967: Wasting syndrome observed in captive mule deer at a Colorado wildlife research facility.

1975−81: Wasting syndrome observed in Toronto Zoo mule deer that came from the Denver Zoo

1978: “Chronic wasting disease” (CWD) diagnosed as transmissible spongiform encephalopathy (TSE)

1979: Recognized in captive mule deer at Wyoming wildlife research facility

1981: Detected in wild elk in Colorado

1985: Detected in wild mule deer in Colorado and Wyoming

1996: Detected in a captive elk farm in Saskatchewan; 38 other linked farms eventually found positive

1997: Detected in captive elk facilities in South Dakota

1998: Detected in captive elk facilities in Montana and Oklahoma: Model Program for Surveillance, Control, and Eradication of CWD in Domestic Elk presented at US Animal Health Association to establish monitoring and control standards

1999: World Health Organization indicates no evidence CWD is transmissible to humans, but advises that exposure should be avoided nonetheless

2000: Detected in wild mule deer in Nebraska and Saskatchewan: Research: molecular studies compare host ranges for CWD, scrapie, and bovine spongiform encephalopathy prions; environmental contamination and subclinical infection contribute to transmission; prevalence estimates in wild populations in Colorado and Wyoming

2001: Detected in captive elk in Kansas : Detected in captive elk in South Korea imported from Saskatchewan: Detected in wild white-tailed deer in South Dakota: USDA declares CWD emergency in captive elk; funds available for disease control

2002: Detected in captive elk in Minnesota, captive white-tailed deer in Alberta, and wild and captive white-tailed deer in Wisconsin: Detected in wild white-tailed deer in Illinois, mule deer in New Mexico, and elk in South Dakota: Joint CWD Task Force of USDA/DOI/States/Universities develops Plan for Assisting States, Federal Agencies, and Tribes in Managing CWD in Wild and Captive Cervids (National CWD Plan): Colorado establishes guidelines to minimize transport of high risk carcass materials: 1st International CWD Symposium (Denver, Colorado): Research: tonsil biopsy as a live animal test; improved high-throughput diagnostics

2003: Detected in wild mule deer in Utah: APHIS funds available for CWD work in captive and wild cervids (through 2011): USDA publishes Proposed Rule for CWD herd certification and interstate shipping program (HCP) to eradicate CWD from captive white-tailed deer and elk: Research: horizontal transmission of CWD likely important in CWD epidemiology

2004: Detected in wild elk in New Mexico : National CWD Plan progress report published and new priorities discussed: Research: environmental sources, decomposed carcasses can contribute to transmission

2005: Detected in captive and wild white-tailed deer in New York, wild mule deer in Alberta, moose in Colorado, and white-tailed deer in West Virginia

2006: Detected in captive white-tailed deer in Minnesota and wild white-tailed deer in Kansas: USDA publishes CWD HCP Final Rule – never implemented: Research: prions in muscles of infected deer; transmitted in saliva and blood

2007: Research: prions in environment more infective in particular (clay) soil types

2008: Detected in captive white-tailed deer in Michigan, wild elk in Saskatchewan, and moose in Wyoming: Research: CWD may be a plausible explanation for local deer population declines in Colorado

2009: APHIS plans to withdraw 2006 CWD Final Rule, issue a new rule based on 2006 rule and 2009 proposed rule: Research: prions shed in feces from deer in early stages of CWD; prions in urine and saliva

2010: Detected in captive white-tailed deer in Missouri and wild white-tailed deer in North Dakota and Virginia

2011: Detected in wild white-tailed deer in Maryland and Minnesota: Severe reduction of USDA funds for CWD work

2012: Detected in captive white-tailed deer in Iowa and Pennsylvania, wild white-tailed deer in Missouri, and wild mule deer in west Texas: APHIS Interim Final Rule for CWD Herd Certification and Interstate Movement and CWD Program Standards published: Research: possible link between scrapie and CWD

2013: Detected in wild white-tailed deer in Pennsylvania

2014: Detected in captive white-tailed deer in Ohio : CWD Program Standards revised: APHIS CWD Final Rule implemented: Research: plants may play role in CWD transmission and environmental maintenance; experimental aerosol transmission in white-tailed deer

2015: Detected in wild white-tailed deer in Michigan and captive white-tailed deer in Texas: Research: plants can bind prions superficially and uptake prions from contaminated soil

2016: Detected in wild elk and white-tailed deer in Arkansas: Detected in a wild reindeer in Norway: CWD found in two wild moose and a free-ranging reindeer in Norway