One of our highest program priorities is preventing the reintroduction of Chronic Wasting Disease (CWD) into the New York State wild deer herd. CWD, similar to mad cow disease, is caused by an infectious particle called a prion. The infectious prions bind to normal brain proteins, causing them to accumulate and create holes in the tissue. While infected deer may take several years to appear ill, the disease is universally fatal. The fact that prion proteins survive for years in the environment, binding to soil and plants, makes this disease very difficult to control once introduced.
Of even greater concern, new evidence from Wyoming indicates that the number of infected deer steadily climbs over time, causing a long-term decline in the deer herd. This disease represents a serious threat to New York State’s wild white-tailed deer population and the captive cervid industry with potentially devastating economic, ecological, and social repercussions.
To decrease the risk of CWD re-entering New York, Dr. Schuler, along with a team of wildlife biologists from NYSDEC, Cornell epidemiologist Hussni Mohammed and data analyst Nick Hollingshead, critically reevaluated NYSDEC's existing surveillance program for CWD. The program now uses a risk-weighted surveillance system that places emphasis on sampling older animals and geographic locations where the risks of disease introduction are higher.
Dr. Schuler also worked with a team comprised of New York State Department of Agriculture and Markets (NYSDAM) veterinarians, Cornell faculty, NYSDEC biologists, managers, and an environmental conservation officer (ECO) to develop plans to mitigate the risk of CWD introduction and effectively respond to an outbreak. The plan addresses activities by hunters, deer processors, taxidermists, the general public, wildlife rehabilitators, and captive cervid operators that have the potential to introduce or disperse infectious materials on the landscape. Education and outreach are the cornerstones of the plan, which is in the final stages of agency review.
In conjunction with NYSDEC Division of Law Enforcement and NYS Dept. of Agriculture and Markets, the WHP created a prevention plan to minimize the risk of re-entry and spread of CWD in New York State. Actions were considered based on expert CWD risk assessment, scientific evidence, field surveys, participant knowledge specific to New York and a desire to develop a plan that both agencies could endorse and implement. The plan was approved in 2018 and has been implemented. For more information on the Chronic Wasting Disease Risk Assessment and Prevention Plan, please visit NYSDEC's site on Chronic Wasting Disease.
The WHP provided background research, economic analyses, and support to the NYS Dept. of Agriculture and Markets to support a regulation banning the importation of all captive white-tailed deer in 2013. WHP participated in a NYSDAM public information session in March 2017 to support the renewal of the deer import ban.
The WHP continues to be a leader in cutting-edge research to inform surveillance of CWD in New York state and across the nation. For example, through SOP4CWD (link), the WHP has published the risk model in New York State:
Krysten L. Schuler, Nicholas A. Hollingshead, Steven Heerkens, James D. Kelly, Jeremy E. Hurst, Rachel C. Abbott, Brenda J. Hanley, Eireann Collins, Kevin P. Hynes, A “hazard model” using risk-weighted surveillance for first detection of chronic wasting disease, Preventive Veterinary Medicine, Volume 243, 2025, 106599, ISSN 0167-5877, https://doi.org/10.1016/j.prevetmed.2025.106599. (https://www.sciencedirect.com/science/article/pii/S0167587725001849)
Developed a theoretical model to pinpoint deer herds with disproportionate outbreak potential:
Brenda J. Hanley, Michelle Carstensen, Daniel P. Walsh, Sonja A. Christensen, Daniel J. Storm, James G. Booth, Joseph Guinness, Cara E. Them, Md Sohel Ahmed, Krysten L. Schuler, Informing Surveillance through the Characterization of Outbreak Potential of Chronic Wasting Disease in White-Tailed Deer, Ecological Modelling, Volume 471, 2022, 110054, ISSN 0304-3800, https://doi.org/10.1016/j.ecolmodel.2022.110054. (https://www.sciencedirect.com/science/article/pii/S0304380022001648)
Leveraged regional surveillance data in conjunction with machine learning to predict where CWD will emerge next:
Ahmed, M.S., Hanley, B.J., Mitchell, C.I. et al. Predicting chronic wasting disease in white-tailed deer at the county scale using machine learning. Sci Rep 14, 14373 (2024). https://doi.org/10.1038/s41598-024-65002-7
And even developed a flexible model to show where to cull if CWD were to ever re-emerge in New York State:
W. David Walter, Brenda Hanley, Cara E. Them, Corey I. Mitchell, James Kelly, Daniel Grove, Nicholas Hollingshead, Rachel C. Abbott, Krysten L. Schuler, Predicting the odds of chronic wasting disease with Habitat Risk software, Spatial and Spatio-temporal Epidemiology, Volume 49, 2024, 100650, ISSN 1877-5845, https://doi.org/10.1016/j.sste.2024.100650. (https://www.sciencedirect.com/science/article/pii/S1877584524000170)
We continue to advance the frontier of best-available CWD surveillance by adapting optimal control to surveillance, incorporating field logistics and costs into the process.
