Summary1
Chronic wasting disease (CWD) is a concerning and complex disease first observed as a syndrome in 1967 and formally described as a spongiform encephalopathy in 1980. It is a fatal infectious prion disease that causes degeneration of the brains of some species of Cervidae (e.g., species of deer, elk, and moose). CWD affects both captive and free-ranging cervids and had been reported in 35 states and five Canadian provinces of North America as of August 1, 2024. The disease has shown patterns of slow epidemic growth in some areas, but tends to persist where it occurs, and can contribute to lower population growth where prevalence is sufficiently high. Misfolded prion proteins (see Box S.1) that cause CWD are shed by infected cervids via saliva, semen, urine, feces, and infected tissues. They are deposited in the environment where they can persist for years. Rates of infection in some free-ranging cervid populations exceed 45% and can be as high as 80% in captive herds.
The potential social and ecological ramifications of the increased spread and prevalence of CWD are serious, including large economic costs for agencies with management responsibilities, for industries that produce or are dependent on cervids and cervid products, and for industries that support cervid hunting and hunting-related tourism activities. The cultural or food security threats that may be felt by Native American or other communities with strong reliance on or traditions tied to cervid hunting can also be considerable. Localized impacts of CWD may differ depending on ecological and social factors.
A considerable foundation of knowledge about CWD was assembled in the first two decades after its formal description. This nascent understanding of host range, diagnostic and surveillance approaches, epidemiology, risk factors, and control strategies informed the first national response plans undertaken in the United States during the early 2000s. Research, surveillance, and management of CWD have further expanded since then. Respective state and tribal governments, federal agencies within the U.S. Department of Agriculture (USDA) and the U.S. Department of the Interior (DOI), affected industries, universities, and other entities have contributed to efforts to understand and control CWD across the United States. Best management practices for free-ranging cervids were reviewed in 2018 by the Association of Fish and Wildlife Agencies (AFWA), which also identified unanswered questions regarding, for example, the precise mechanisms of transmission, evolution of different prion strains, effects of population density on transmission, transmissibility to other species, and the effects of human factors on the disease spread.
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1 This summary does not include references. Citations for the information presented herein are provided in the main text.
In 2020, Congress passed America’s Conservation Enhancement (ACE) Act (P.L. 116-188), which directs the U.S. Fish and Wildlife Service (USFWS) to lead a CWD Task Force to “leverage the collective resources of Federal, State, and local agencies, [tribal communities], and foreign governments, and resources from private, nongovernmental entities” and develop an action plan for addressing CWD in the United States. The ACE Act encouraged the Secretaries of the Interior and Agriculture to commission the National Academies of Sciences, Engineering, and Medicine (the National Academies) to produce “a special resource study to identify the predominant pathways and mechanisms of the transmission of chronic wasting disease in free-ranging and captive populations of cervids in the United States.” This report summarizes the state of knowledge related to CWD that can aid the task force when prioritizing research and developing future CWD management strategies.
THE STUDY CHARGE
In collaboration with the USDA and the USFWS, the U.S. Geological Survey (USGS) requested the National Academies to convene a committee to draw conclusions about the state of knowledge regarding CWD. An ad hoc committee of 11 experts conducted a retrospective examination of published and ongoing research regarding infectious doses and concentrations, modes of transmission, the means of geographic spread, the effectiveness of interventions to reduce transmission or spread, and the human societal implications of CWD. This report synthesizes that committee’s efforts. The audience for this report includes the study sponsors and state, provincial, tribal, and federal agencies with interest in or responsibility for managing free-ranging or captive cervids; conservation and hunting groups or individuals; the captive cervid industry; other individuals and groups interested in CWD and cervid management; members of Congress; and the public at large.
The report attempts to identify the levels of uncertainty of CWD-related knowledge and management practices. The study charge did not request recommendations for future actions; the committee provided conclusions based on existing evidence. The intent is to aid future decision makers in the prioritization of research and the further development of CWD management and mitigation strategies with the understanding that the complete control or elimination of CWD at the national or local scales may not be within reach.
DISEASE DESCRIPTION
The process by which CWD prion infection leads to disease (i.e., pathogenesis) largely parallels what is seen with other prion diseases (see Box S.1), but its modes of transmission and management are different. Oral-nasal contact with CWD prions is thought to be the most common mechanism of the transmission of CWD prion. Following natural exposure and infection, the disease progresses for more than a year. Incubation periods differ depending on the prion strain and dose, the route of exposure, the animal species involved, and, importantly, the genotype (e.g., the genetic makeup of the cervids). Infected cervids may show little to no outward signs of disease for most of the disease’s incubation period, but late-stage infected cervids show signs such as changes in behavior and progressive deterioration of body condition that is expected to lead to the death of the infected animal.
A gene with a primary role in CWD infection, transmission, and pathogenesis encodes the normal prion protein (PRNP). This gene varies within cervid species and between cervids, cattle, and sheep. Gene variation results in differences in disease susceptibility and in what is referred to as the “species barrier” (e.g., that which prevents the crossing of the disease from one species to another). No cervid PRNP genotype identified, to date, is completely resistant to infection. Although prion disease susceptibility depends on a functional prion protein, the PRNP gene is likely not the only gene involved in disease pathogenesis.
Laboratory studies have identified multiple strains of CWD prions. The pathogenesis of the more common CWD prion strains has been well studied. Disease resulting from different strains of CWD prions in the United States are difficult to differentiate based on clinical patterns and pathology. Current techniques for prion strain evaluation do not allow a detailed analysis of the abnormal protein structure, and there is insufficient data about specific host species, their PRNP genetics, and their locations to allow comparison of data from different studies.
EVALUATION OF THE GENERAL STATE OF CWD KNOWLEDGE
Science, collaborative research, and experience have created a substantial body of knowledge regarding CWD in free-ranging and captive cervids. However, some knowledge is unpublished and therefore implicit. Knowledge that exists but is not publicly available may be based on prior or ongoing research or on anecdotal information. Decisions and policies informed by this knowledge could be correct but may also be fraught with uncertainty. The strategic efficacy and cost-effectiveness of those decisions may not be optimal. Furthermore, CWD-related policies may not be fully understood by the public because of a lack of access to supporting information. This could result in CWD control activities being implemented inconsistently or without persistence. More freely available data and information could resolve many uncertainties about CWD. Examination of existing data could resolve many open questions, but some scientific knowledge gaps related to CWD will require new information gained through targeted laboratory and field studies and research.
TRANSMISSION AMONG CERVIDS AND FROM THE ENVIRONMENT
CONCLUSION 1: Multiple drivers and epidemiological factors affect CWD transmission and infectivity. The precise roles, interrelationships, and relative importance of these factors are not fully understood, cannot be fully quantified, and may differ for captive and free-ranging cervid populations.
Given the difficulty of studying CWD in natural settings, much knowledge regarding CWD derives from controlled experimental studies. However, data derived from controlled investigations—including data related to transmission—may have limited application to analogous processes occurring in nature. For example, the infectious dose, repeated exposure, persistence of CWD prions in the environment, duration of incubation and pathogen shedding by the host, molecular makeup of the prion itself, and host genetic differences all influence transmission in laboratory settings. These are difficult to study in natural settings. The effects of numerous anthropogenic factors that likely contribute to CWD transmission and geographic spread also have not been quantified.
TRANSMISSION TO NON-CERVID SPECIES INCLUDING HUMANS
CONCLUSION 2: As of this writing, no cases of CWD transmission to humans have been diagnosed or reported, nor has natural transmission to non-cervid animal species been detected.
As the prevalence and geographic distribution of CWD increase, so does the risk of exposure to other potentially susceptible species. However, cases of natural CWD infection of species outside the cervid family have not been reported. CWD prions have been experimentally transmitted to species such as pigs, raccoons, ferrets, cattle, sheep, and various rodents. Most of those transmissions were achieved via injection directly into the brain rather than natural exposure routes. CWD prions can be found in fecal material of free-ranging carnivores and scavengers, such as cougars, coyotes, and crows, but are thought to pass through their digestive systems without infecting them.
The potential for transmission of CWD to non-cervid species (including humans) by more natural routes of exposure (e.g., ingestion) is unknown. There is concern among some observers that communities that harvest wildlife and plants from areas of heavy cervid use or employ traditional medicinal or ceremonial practices may experience disproportionate or unique exposures to the CWD prion that may warrant some investigation. The collective results of research to date using a variety of molecular and animal models suggest the species barrier between humans and CWD prions is likely high, though perhaps not absolute. The zoonotic potential of each CWD strain needs to be assessed. Some laboratory studies incorporating experimental amplification assays and surrogate models of human susceptibility (e.g., some species of non-human primates and transgenic mice expressing human prion proteins) have suggested that certain strains of CWD prions may have some potential to induce the human prion protein to misfold. Those data need to be interpreted with caution as low levels of prions—perhaps below the level of clinical relevance—were amplified. The route of inoculation (e.g., oral versus direct injection into the brain) and strains being studied may account for some of the observed experimental variability.
SPREAD OF CWD
CONCLUSION 3: The known geographic distribution of CWD is expanding. However, the distribution is incompletely understood and likely underestimated. Inconsistent surveillance has compromised knowledge about changes in CWD distribution over time in the United States.
Organized CWD surveillance was minimal prior to 1997, but had been undertaken in several states and Canadian provinces by 2000, and has been practiced to varying degrees across the United States since 2002. The details of recent and historical surveillance efforts are unevenly available to the scientific community and the public. Despite that, and despite the difficulty detecting focal CWD outbreaks and measuring real-time spread, ample evidence suggests that the number of cases and geographic distribution of CWD have increased. Timelines of geographic spread, however, cannot be inferred reliably based only on the chronology of first detections and are likely underestimated due to inconsistently applied surveillance practices. Because management of CWD is more challenging when the disease is widespread, understanding epidemic expansion and timelines is important.
CWD surveillance is resource-intensive, costly, and unevenly implemented in many regions, but there are effective, sustainable, and coordinated surveillance strategies applicable to both captive and free-ranging cervids despite the unique challenges presented by each. Information gained through surveillance is necessary to improve scientific understanding of the epidemiology and geospatial characteristics of CWD.
CONCLUSION 4: Natural movement of infected cervids and other epidemiological factors are responsible for the local distribution of CWD. Human-mediated movement of infected cervids (i.e., transport of live, dead, captive, or free-ranging cervids) and infected cervid products for commerce, recreation, conservation, and other purposes increases the likelihood of CWD spreading to new geographic areas in unpredictable ways.
Multiple natural mechanisms (e.g., natural movement of infected cervids among and between herds, shedding of prions by infected cervids into the environment, and spread of CWD prions by predators and scavengers) are known or suspected to be responsible for CWD spread within a geographic region. Human activities and behaviors likely have contributed to rapid and less predictable spread of CWD across longer distances than might be expected to occur naturally. For example, transport of infected live cervids is known to spread the disease across state and international lines and to new areas far from where CWD had been previously detected, and the transport of infected dead cervids or of infected cervid parts or products (e.g., meat, velvet, and urine products)2 is suspected but not yet demonstrated to have had a similar role in some cases. On the local scale, it is conceivable that
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2 Discussions of cervid parts or products are intended to describe their suggested but as yet undemonstrated roles in contributing to the spread of CWD to cervid populations. This text does not describe the potential risks to humans of contact through consumption of cervid meat or through environmental contact.
behaviors such as improper disposal of carcass parts3 and the use of attractants or bait to encourage congregation of cervids could increase the spread of the disease, but these have not been documented. While there are numerous state, provincial, and tribal bans and carcass import regulations prohibiting the movement of select portions of hunter-harvested cervids across jurisdictions,4 regulatory compliance is not well studied. How attractants, feed and feeding sites, carcasses, farm equipment, captive cervid pens, and across-fence contacts contribute to CWD transmission is being studied.
DIAGNOSTIC METHODS
CONCLUSION 5: Official USDA postmortem CWD diagnostic approaches are useful for disease surveillance in both free-ranging and captive cervids. Newer, as yet unapproved, detection approaches may have more wide-ranging applications, including live-animal testing and screening of cervid byproducts, environmental surfaces, and other relevant materials.
Screening and diagnostic methods used to surveil potential environmental contamination and to monitor for changes and potential emergence of new strains are needed as adjuncts to established diagnostics to confront management challenges where CWD occurs. Since the early 2000s, CWD detection and surveillance have relied on standardized immunohistochemistry (IHC) or enzyme-linked immunosorbent assay (ELISA) protocols for postmortem detection of the misfolded prion protein in lymphoid and neural tissues. These tests, officially recognized by the USDA, may only be conducted by approved diagnostic laboratories.5 They are not widely applied to live-animal testing and cannot be used for screening select biological and environmental samples that may have important roles in CWD transmission (e.g., soil, plants, insects, or bodily waste). There is a need for rapid, inexpensive, field-deployable tests useful for early CWD detection in live cervids and for environmental surveillance.
Amplification assays for detecting CWD prions have been developed (e.g., the protein misfolding cyclic amplification [PMCA] assay and the real-time quaking-induced conversion [RT-QuIC] assay), but none are USDA-approved. When fully evaluated, these tests may be shown to be faster, more versatile, and more sensitive than their approved counterparts. They have proven useful for screening a range of matrices including tissue biopsies, bodily fluids, and environmental samples that are unsuitable for IHC or ELISA screening, and they have the potential to accommodate high testing volumes. However, because of variability in testing results, these amplification assays require standardization and continued validation before being considered for approval. A better understanding of the relationship between detection and infectious dose is needed.
CONTROL
CONCLUSION 6: Well-founded epidemiological principles inform strategies for CWD prevention or control in both captive and free-ranging cervids, beginning with effective early and ongoing surveillance and followed by timely, aggressive, sustained local response upon the presence of CWD being discovered. Although imperfect, methods based on those principles can reduce or prevent large increases in prevalence and slow the spread of CWD when properly applied.
CWD is transmitted both directly (i.e., animal to animal) and indirectly (from the environment). As such it cannot be controlled through a single intervention as have other prion diseases (e.g., through managing feed, as for bovine spongiform encephalopathy). Current and collective knowledge regarding CWD and its control, albeit incomplete, is based on sound epidemiological principles demonstrated to be effective in the management of both animal and human infectious diseases. That knowledge is sufficient to inform interim comprehensive control strategies to slow the occurrence and spread of the disease at the local and national levels. For example, the knowledge
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3 For example, in a manner that could contaminate the environment or be a source of infection to cervids.
4 See https://cwd-info.org/state-and-province-carcass-import-regulations/ (accessed June 22, 2024).
5 This sentence was revised after release of the report to clarify that Western blot and histopathological examination are also approved test methods.
that infected hosts, their residual secretions and excretions, and their carcasses are potential sources of infectivity can be used to inform control measures such as implementation of risk-based and targeted culling, appropriate carcass handling, compulsory surveillance, and regulation of commercial movement of cervids and products.
Experience gained from the management of other infectious diseases indicates that early and ongoing surveillance and aggressive and sustained local response once CWD is detected can be effective at preventing and controlling CWD in both captive and free-ranging cervids. Other practices based on sound epidemiological principles include
- situational awareness of CWD prevalence, host and environmental factors, and animal movements based on risk assessments;
- reduction or elimination of human-facilitated spread of infected cervids or infected cervid products;
- identification, elimination, or reduction of potential sources of indirect exposures;
- development of realistic and plausible control goals incorporating socioeconomic, political, and cultural dimensions in a collaborative and adaptive framework; and
- preemptive public messaging and education on CWD and prospects for control.
Infection of captive cervid herds can be limited with strong biosecurity and preventive management—for example, through certifying animal sources and applying quarantine principles to infected herds. However, these cervids are still at risk, particularly in areas where CWD occurs among free-ranging cervids. The USDA Animal and Plant Health Inspection Service CWD Herd Certification Program (HCP) is a voluntary, state-administered program intended to prevent and reduce CWD transmission and spread in captive cervid herds. The HCP has contributed to limiting interstate spread of CWD; however, the total number of enrolled herds has decreased in recent years. Detection of CWD in HCP-certified herds suggests that current biosecurity measures need to be reconsidered and that indirect transmission within and among herds needs further investigation. HCP participation, alone, is not sufficient to control CWD transmission and spread. In-depth epidemiological analyses of CWD-infected herds would result in better understanding of risk factors and inform improvements in disease prevention and biosecurity.
Beyond the general CWD control measures described above, and based on accepted epidemiological practices, CWD control measures expected to be effective in managing free-ranging populations and controlling CWD prevalence include using targeted local culling or harvest to reduce host abundance and sources of infection, and regulating or banning baiting and feeding.
Measuring the effectiveness of CWD control strategies for free-ranging herds is challenging. Underestimating the scope and scale of the disease, constraints on design and implementation of control programs, and a lack of sustained support among interested and affected parties have affected outcomes in most situations. Knowledge gaps may result in management strategies with high levels of uncertainty. Thorough epidemiologic analyses of newly detected outbreaks are warranted to improve understanding of risk factors and improve disease prevention and biosecurity measures. Collaborative efforts to evaluate and understand the collective cross-jurisdictional portfolio of evidence and to convert existing but inaccessible or anecdotal information into accessible and actionable data will enhance the collective ability to blunt the effects of the disease in the short-term and inform adaptive management decisions. Ongoing research may then inform longer-term control solutions.
CONCLUSION 7: Differing philosophies and approaches to CWD management adopted by agricultural and wildlife management authorities at different levels of government impact the effective control of CWD in the United States.
A variety of local, state, tribal, and federal entities operating under different authorities, jurisdictions, regulations, guidelines, social pressures, and management strategies all have different responsibilities and approaches for managing CWD—often with inadequate resources. The result is a patchwork of non-standardized prevention and control strategies that are unevenly and inconsistently adopted, implemented, and evaluated.
Government agricultural agencies are largely responsible for managing captive cervids (generally regulated as livestock) for the economic benefit of producers and to meet market demand for cervids and cervid products.
Control efforts are focused largely on protecting captive cervids from infection or on preventing the spread of CWD among captive cervid facilities. They may reduce the spread of disease from captive to free-ranging cervid populations, but they cannot address the spread of disease once transmitted into free-ranging populations.
In contrast, state, tribal, and federal wildlife management agencies often focus on maximizing recreational, economic, ecological, and societal values associated with free-ranging cervids. These goals may conflict with recognized successful CWD-reduction approaches. For example, culling appears to be an effective practice for controlling the prevalence of the disease in some situations, but this practice may conflict with the public preference for seeing greater numbers of cervids in the wild or using hunting as a control tool. Tribal agencies may have the additional challenges of balancing cultural and traditional values, food sovereignty, and a subsistence economy with wildlife management priorities, while also having limited agency capacity and high administrative burden in acquiring federal funding and grant management.
Improved disease management is more likely with coordinated, complementary, collaborative, and sustained control strategies among management agencies with responsibilities for both captive and free-ranging cervids. These strategies will be based on improved understanding of the underlying genetics of reduced CWD susceptibility, and the development of and access to improved diagnostic approaches, as described earlier. Data sharing and comprehensive data analyses of CWD outbreaks are warranted. Adaptive CWD management strategies that can be customized and modified for various jurisdictions and situations have substantial advantages and merit.
CONCLUSION 8: Prevention is key to controlling the spread of CWD given that existing tools and technologies make eradication of CWD in captive or free-ranging cervid populations, once established, improbable. Ongoing and effective surveillance programs can facilitate early detection and response.
CWD surveillance is not equivalent to management, but it is essential for informing improved prevention and control programs. Timely detection will be more likely with ongoing and effective surveillance programs. Effective and less resource-intensive rapid response is more likely with early timeline detection of CWD. Experience controlling infectious disease indicates that an aggressive response to CWD when detected in a new geographic region early in an outbreak can result in the local elimination of the disease in at least some circumstances (although future re-emergence of the disease is possible). If CWD becomes established among local free-ranging cervids or in a captive herd, effective management and control strategies may keep CWD prevalence at low levels and limit the buildup and overall contribution of environmental contamination to ongoing transmission. However, it is yet unclear how long low prevalence levels can be maintained. Presently, there are no environmental treatments or habitat modifications that effectively reduce or eliminate prions in the environment. Quickly removing infected captive cervid herds from the landscape is likely important in controlling disease spread where CWD is not already established in the surrounding area.
CONCLUSION 9: Genetic selection, vaccines, environmental decontamination, and therapeutic options are being investigated as tools for CWD control but need further inquiry and review. Although none of these approaches can, at present, replace existing forms of management and control, in the future they may, in combination with current methods, reduce CWD on the landscape.
Current strategies focusing on active surveillance and regulations covering the movement of cervids and their byproducts are imperfect but effective. Targeted research to develop and expand new tools and strategies such as genetic selection, vaccines, environmental decontamination, and therapeutic options to prevent or control CWD are essential and deserve further study. However, the following must be considered:
- Selective breeding of animals less susceptible to CWD as a management tool in captive cervid herds may be constrained because of the limited understanding of the different rates and lengths of exposure in herds and exposure to different CWD prion strains. Managing CWD in free-ranging populations through selective breeding is not feasible. Longitudinal studies in both captive and free-ranging populations would facilitate a better understanding of genetics on relative susceptibility to prion infection and prion shedding.
- Vaccine development efforts are in the early stages of development, have yielded mixed results in rodent models, and have thus far been largely unsuccessful in cervid hosts. The same is true for other potential therapeutic options. Without better knowledge of cervid and prion biology and cervid immunity against different CWD strains, vaccines and other therapies are not ready for use. Development of remote delivery systems (e.g., oral bait) may facilitate reductions in disease prevalence, at least in captive cervids.
- Environmental decontamination protocols to date include the removal of topsoil and treatment of landscapes with hydroxide, treatment of landscapes with humic acid, and exposure to high temperatures. These treatments have yet to be demonstrated as effective and ecologically responsible. Implementation of decontamination protocols may be difficult and impractical in many cases at scale. Heterogeneities in soil types, vegetation, and weather over many acres may alter the efficacy of a protocol.
- Limited laboratory evidence suggests that the impacts of CWD or its infectivity can be reduced in biological samples through therapeutic options, but there is no evidence regarding their use in live cervids or the environment.
SOCIAL AND JURISDICTIONAL FACTORS
CONCLUSION 10: Human behaviors can influence the transmission, spread, and consequences of CWD. Interest groups hold diverse viewpoints regarding the seriousness of CWD and about its spread, prevention, and control; their decisions may not always be informed or influenced by the best available science.
Complex human dimensions can be as influential as biological factors in the transmission, spread, and management of CWD. Lack of understanding of the social, economic, and cultural human dimensions with respect to CWD is a significant barrier to CWD management. Interested and affected parties hold different views, values, beliefs, and economic interests, and their behaviors and decision-making differ greatly. Division among them can result in a lack of participation, compliance, and collective support for CWD actions and programs. The lack of communication and coordination mechanisms related to data collection and information sharing across jurisdictions precludes an evaluation of control measures for their efficacy.
The integration of multiple disciplines and expertise—including sociology, economics, behavioral science, anthropology, and others—is needed to create innovations and strategies to better leverage human dimensions in CWD management. Translation of CWD science into decision-making requires a fuller understanding of CWD gained through collaborative and coordinated open data-sharing across disciplines, organizations, and governmental entities. Such collaboration will be critical to mitigate the negative impacts of the disease on cervid population levels; minimize socioeconomic impacts of the disease; reduce potential misinformation; and evaluate and launch effective, sustainable interventions.
ECONOMIC ANALYSES
CONCLUSION 11: Existing data gaps make CWD-related economic measurements and analyses difficult to quantify. These deficiencies can result in a lack of appreciation of the full impact of the disease and in the inability to evaluate and compare the direct and indirect costs and benefits of various management strategies.
CWD is becoming more costly and consequential to manage as a result of the increasing number of cervids affected and their geographic distribution. The lack of accurate and current economic information may result in some entities and individuals undervaluing the impacts of CWD and may diminish a sense of urgency to act on CWD. Expenses associated with CWD management represent economic vulnerabilities for the federal, tribal, state, and local entities with CWD-related authorities and responsibilities. Tribal wildlife management entities are further constrained by the lack of resources, lack of staff, and high levels of administrative burden associated with the complicated processes for transfer of federal funding and grant management. Agencies may be unequipped or underequipped to meet the current challenges of CWD, and current resources may be insufficient to address CWD as it continues to spread.
Estimates of opportunity cost functions allow the prediction of future consequences of additional captive or free-ranging herds becoming infected with CWD. However, although some data regarding state and federal costs and expenditures are available, the full economic burden or impact of CWD at any jurisdictional level cannot be quantified. At present, most jurisdictions can produce only rough estimates of the numbers and locations of free-ranging cervids and herds. Costs and benefits of CWD management options will depend on multiple variables including the current and predicted populations of both captive and free-ranging cervids, local economies and markets, and a range of human dimensions. Analyses of captive and free-ranging population levels in a wide variety of locales, and in concert with robust CWD surveillance programs, would support cost-benefit analyses of localized CWD management activities.
MOVING FORWARD WITH A COORDINATED RESPONSE
Limited knowledge related to many critical aspects of CWD, its epidemiological and biological complexity, and the diversity and competing views of various interested and affected parties make CWD challenging to address and control. However, the ability to adopt scientifically supported strategies can result in a productive, cost-effective set of interventions capable of slowing the transmission and spread of the disease and its impacts. Science, collaborative research, and experience continue to provide new knowledge and understanding of CWD in free-ranging and captive cervids. Further exploration of how to apply this knowledge in a collaborative, coordinated, and sustained manner across agencies with management responsibilities, particularly regarding the management of free-ranging populations, would improve captive and wild cervid management decisions aimed at altering the trajectory of the rate of change of CWD.
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