Decision analysis in support of proactive planning for chronic wasting disease in Vermont, USA

Executive Summary

Chronic wasting disease (CWD) is a fatal disease of deer, moose, and other cervids that is spreading across the United States (U.S.). As of December 2025, the nearest infected wild deer population to Vermont was in Pennsylvania, about 225 miles away; however, the disease has been detected closer to the state in New York and Quebec, Canada, but those detections are assumed to have been isolated and removed without additional spread in wild populations or captive facilities. The primary pathways of arrival to Vermont are natural spread in wild deer, import of infected live animals to captive cervid facilities, or disposal of imported infected deer parts on the Vermont landscape. Once CWD arrives, significant changes to many ecological, social, and economic resources are expected.

Many State and Federal agencies could have a role in managing CWD, before and after its arrival.

• Vermont Department of Fish and Wildlife (VDFW) has statutory responsibility for managing the wild deer and moose populations in the State, including through hunting;

• Vermont Agency of Agriculture, Food and Markets (VAAFM) is responsible for oversight of the nine captive cervid facilities in the State;

• Vermont Department of Forests, Parks and Recreation (VFPR) manages State Forests and Parks, which provide habitat for deer and recreational access for hunters;

• Vermont Department of Health (VDH) provides information and guidance to the public that enables them to make informed decisions that can affect their health, including whether and how CWD poses any risk to humans;

• U.S. Fish and Wildlife Service (USFWS) manages two National Wildlife Refuges in the State, which provide public access, including to hunters;

• U.S. Department of Agriculture Wildlife Services can provide contractual support for wildlife management, including targeted reduction of deer populations; and

• U.S. Forest Service manages extensive forest resources in the State, which provide habitat for deer and access for hunters.

These agencies have expressed interest in co-development of a long-term collaborative plan for management of CWD. From September 2023 through September 2025, they engaged in a series of meetings, facilitated using the principles of structured decision making to explore potential proactive and reactive management strategies, and how well those strategies might perform against the fundamental objectives being sought by the agencies. As part of this work, the U.S. Geological Survey and the University of Vermont developed quantitative predictive models to allow evaluation of alternative strategies against the fundamental objectives.

The agencies identified seven fundamental objectives for a long-term (20-year) CWD management plan that arise from their enabling legislation and missions:

• Maximize herd health of native cervid populations in the state of Vermont;

• Maximize the public benefit of cervids (consumptive and non-consumptive);

• Minimize harm to other species, unique ecosystems, and forests;

• Minimize costs, staff time, and workload associated with CWD management;

• Minimize the effect (or potential effect) that CWD has on public health;

• Minimize the effect of CWD and its management on local economies; and

• Maintain opportunities for private landowners to engage in agricultural pursuits.

In initial work to explore the effects of actions on the objectives, six broadly different alternative strategies were developed, where the strategies differed in philosophy, investment, timing, and proactive versus reactive emphasis.

• Under the Status Quo strategy, existing protocols would remain in place until CWD is detected in the State, at which point an increase in surveillance and harvest opportunity would be implemented.

• The Heavy Outreach strategy would rely primarily on outreach and communication with the public, notably hunters, to delay arrival, slow transmission, and mitigate impacts.

• The Reduce Arrival strategy would invest primarily in proactive measures including both outreach and regulatory changes to slow arrival of CWD to the State.

• The Prepare and React strategy would invest primarily in reactive measures after CWD arrives, with preparatory measures to detect it as early as possible and have in place the management tools to deploy upon arrival.

• The Prevent and React strategy would make a moderate investment in both proactive and reactive measures.

• Under the Kitchen Sink strategy, extensive investment would be made in both proactive and reactive measures.

The estimated mean time to arrival of CWD in the State is 7.7 years under the Status Quo strategy. Concerted efforts to delay arrival could increase this time to 10.6 years, by significantly reducing two of the three arrival pathways. It will, however, take an average of 15−30 years after arrival to detect CWD in the State assuming effort is spread evenly throughout the State, owing to its slow growth in the deer population. Investment in surveillance leads to earlier detection and hence, an earlier opportunity to implement reactive measures.

There are notable trade-offs among the alternative strategies in their ability to achieve outcomes of interest to the State, based on the analysis described in this report.

• The arrival and spread of CWD can be slowed quite significantly, particularly with a combination of proactive and reactive measures, with the Kitchen Sink showing a 6-fold reduction in prevalence over 50 years compared to the Status Quo strategy.

• The number of CWD-positive deer consumed by hunters, their families, and their friends largely tracks the prevalence of CWD in the population, although increased outreach efforts also contribute to reduced consumption.

• Deer harvest, and the economic benefits associated with it, is expected to increase under aggressive CWD management strategies, because the strategies encourage higher harvest to manage the disease, and lower prevalence of CWD keeps more hunters participating.

• The positive outcomes associated with more aggressive proactive and reactive measures are counterbalanced by increases in costs to agencies, for surveillance, sharpshooting, outreach, and captive cervid management.

Captive cervid farm operations in Vermont were estimated to be a low-risk introduction pathway because of the stringent regulations, agency oversight of importation, and disease testing that is already occurring. However, actions by VDFW could reduce the risk of spread from wild to captive deer. The more aggressive CWD management strategies reduce CWD prevalence and increase the long-term opportunity for captive cervid operations. The one exception to this is the Kitchen Sink strategy, which seeks to reduce the risk of arrival of CWD by proactively closing captive cervid facilities.

The size of the statewide deer population is expected to be about the same in 20 years across all strategies, with all alternatives resulting in a decrease of about 5% compared to current population size estimates. In some strategies, the deer population decreases because of the effects of CWD; in others, the deer population decreases because of increased hunting that slows the transmission of CWD.

After considering the results from the analysis of the six initial strategies, the participating agencies were interested in more carefully exploring the tradeoffs among three of the objectives: long-term prevalence of CWD in the State; the cost of management of CWD; and the opportunity for private farms to participate in captive cervid farming. An additional 256 strategies, which were permutations of the constituent actions under consideration, were created and analyzed. These results showed that the most effective way to keep CWD prevalence low over the long term was extensive surveillance to allow early detection, followed by sharpshooting or other targeted removal at a local level, to continually eliminate or reduce new incursions of the disease. This approach, however, is quite costly, so the balance between effort and effect was important to the agencies. Regarding captive cervid operations, proactive closing of captive cervid facilities does slightly lower the long-term prevalence of CWD and substantially diminishes the long-term costs of closing infected captive cervid farms in the future, but comes at the cost of farming opportunity.

In September 2025, the participating agencies expressed a collective interest in a strategy that preserves captive cervid farming opportunities, invests heavily in surveillance for early detection of the disease, and prepares for targeted removal of deer when detections occur. Such a strategy, while potentially costly, achieves many of the objectives sought by the participating agencies on behalf of the people of Vermont. The agencies, without yet making any commitments, intend to undertake work to develop the details of this plan, discuss its aspects with stakeholders, and build support for its long-term implementation.