Best Management Practices for Surveillance, Management, and Control of Chronic Wasting Disease in Free-Ranging Cervid Populations

Symposium
ROOM: CC, Room 25A
SESSION NUMBER: 31
 
Chronic Wasting Disease (CWD), an infectious prion disease of cervids, is arguably the most important disease affecting North American wildlife. Renewed interest in CWD has arisen from disease detection in multiple new geographic locations, including Europe, research reports of population level impacts on deer and elk, and concerns regarding the potential for inter-specific transmission, including into primates. CWD is no longer a parochial issue confined to interest by a few western states; wildlife managers across the continent are faced with conducting planning and surveillance activities, and unfortunately, too often, responding to CWD when it is detected. To assist wildlife managers and decision-makers plan and respond to CWD, the Association of Fish and Wildlife Agencies has recently compiled a set of best management practices. This symposium will include presentations based on those best management practices presented by experts with experience developing and implementing actions to understand and address the biological, ecological, social, and political impacts of CWD. The goal of the symposium is to provide wildlife managers and administrators a synthesis of current tools and ideas available so they can implement their own suite of management practices at the state or provincial scale. Presentations will be informative to novice disease managers struggling with developing surveillance programs and herd management plans to veteran decision-makers leading CWD management programs. Following the morning and afternoon sessions, presenters will convene in a panel to share opinions and engage the audience in identifying priority gaps and needs for future work to better detect and manage CWD.

8:10AM Looking Back at 50 Years of Chronic Wasting Disease: Lessons Learned as We Move Forward
  Michael Miller; John Fischer
Chronic wasting disease (CWD), 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. As of May 2018, CWD had been reported in captive and/or free-ranging cervids in the United States (25 states), Canada (three provinces), South Korea, Norway, and Finland. With few exceptions (New York and perhaps Minnesota), once in the wild the disease has persisted in the face of widely varied control attempts. Natural and anthropogenic factors have contributed to the geographic spread and persistence of CWD: Natural factors include prolonged incubation, multiple routes of agent shedding, the agent’s environmental persistence, and migratory and dispersal movements of wild cervids. Anthropogenic factors include movements of infected live animals (and perhaps infectious tissues and other materials), concentrating susceptible host species, and other artificial wildlife management practices. Many facets of CWD biology and ecology now are understood, but science informing effective management and control strategies remains incomplete. Eradicating CWD appears infeasible given its extensive distribution and other epidemiological attributes. Regardless, adaptive approaches for containing foci and reducing infection and transmission rates have shown some promise and deserve further attention. Such pursuits undoubtedly will be more difficult to garner and maintain support for in sociopolitical climates ranging from apathetic to combative, particularly when control prescriptions impinge upon or conflict with commercial and public hunting interests. We believe there are two important motivations for making progress toward sustainable containment and control strategies for CWD in the coming decades: First, data from several sources suggest that heavily-infected cervid populations will not thrive in the long-term. Second, data on CWD prions and experience with other animal prion diseases suggest it is prudent to minimize human exposure to these agents.
8:50AM Development of Population and Herd Plans for Response to CWD
  Jennifer Ramsey
As chronic wasting disease (CWD) continues to be detected across North America, the benefit to wildlife management agencies of developing CWD management plans has become clear. In many cases, disease is already well-established by the time it’s detected, so a prompt but methodical response is often appropriate and critical when considering the effects on the resource, the state or provincial economy, and potential concerns raised by public health agencies. A plan that can be adaptable to a variety of circumstances, and which is developed using the best available science, having clearly identified objectives, and which includes stakeholders in the development process will facilitate more efficient allocation of available resources, allowing a prompt response and improved public perception.
9:10AM Managing the Human Dimensions of CWD
  Lou Cornicelli
The wildlife management environment functionally has three components – wildlife, habitats, and humans. It can broadly be stated that everything that does not directly involve wild animals or their habitats is about humans. The human component of the management environment falls within the field of study known as human dimensions, which can be defined as the application of the social sciences to natural resources management issues. Human dimensions research is essential for understanding the potential impacts of chronic wasting disease (CWD). While there is a growing body of literature devoted to understanding stakeholder perceptions, attitudes and beliefs about CWD, the amount of published information is limited when compared with disease ecology studies. States and provinces should be very concerned about the potential impacts of CWD on their landscape as the disease may be partly responsible for declines in hunter numbers, especially when considering potential human health implications. While research to date has not empirically demonstrated a human health risk, preliminary experimental studies suggest there may be some risk. This perception of risk has the potential to also impact trust in the wildlife agency, the agency’s ability to effectively manage the disease (e.g., lack of support from hunters and landowners), and negatively impact local economies, among others. A top-down, authoritative solution that does not include stakeholders and social science research may ultimately harm credibility and nullify a comprehensive (and effective) response. States should consider a variety of tools, including social science surveys of stakeholders within CWD affected areas, detailed plans that address internal and external communications, increased stakeholder engagement processes, and timely website updates to fully engage on this issue. Without knowledge of these human dimensions needs, agencies will be poorly positioned to meaningfully respond to this significant disease challenge.
9:30AM Panel Discussion
 
09:50AM Break
12:50PM Surveillance Strategies in Presumed CWD-Negative Populations
  Brandon A. Munk; Daniel P. Walsh; Mark G. Ruder; Krysten L. Schuler; Colin M. Gillin
Active surveillance for chronic wasting disease (CWD) should be a priority for any agency that manages wild cervid populations. Recent detections in free-ranging ungulates in Norway, range expansion in North America, the challenge of effective control, and recent research suggesting non-cervid species may be susceptible, have heightened concerns over the continued spread of CWD, and its potential to affect human and animal health. Once the disease is present, environmental contamination likely plays a significant role in the spread and maintenance of the disease; neither environmental decontamination nor eradication of CWD, once established in a population, are feasible at this time. Early detection, when CWD prevalence is low and seeding of the environment is minimal, provides the greatest opportunity for CWD management to be effective. However, resources available to conduct active surveillance for CWD are often very limited, despite the clear need for robust surveillance. To improve the efficiency of surveillance programs, wildlife managers should incorporate spatial and demographic risk factors associated with CWD into a weighted or risk-based surveillance strategy that is adaptable and tailored to the state, province, or population in question. Examples of how these concepts may be applied to increase surveillance efficiency and efficacy will be presented and discussed.
1:10PM Applied Surveillance: Lessons Learned From Hardly Looking to Looking Hard
  Jennifer R. Ballard; M. Cory Gray
Chronic wasting disease (CWD) is a fatal, neurologic disease of cervids caused by a misfolded protein known as a prion. Initially described in mule deer from Colorado and Wyoming, CWD was long considered a regional issue of the western United States. More recently, the detection of CWD in new locations, including several in the eastern and Midwestern U.S., concerns about the population-level effects of CWD, and the potential for interspecies transmission have raised considerable alarm among wildlife managers nationwide. Between 1997 and 2015, the Arkansas Game and Fish Commission tested 6,656 white-tailed deer (Odocoileus virginianus) and 204 elk (Cervus elaphus) for CWD with no detections of the disease during that time. In 2002, the agency placed a moratorium on the importation of live cervids into the state. In 2005, restrictions were placed on the importation of intact cervid carcasses, with more conservative restrictions being implemented in 2013. In 2006, a moratorium was placed on the licensing of new captive cervid facilities followed by increased inspections of existing facilities; also in 2006, the agency developed a statewide CWD Response Plan. Despite the implementation of standard preventative measures and a variety of surveillance strategies, Arkansas was found to be positive for chronic wasting disease in February of 2016. Localized, random sampling immediately following initial detection identified a 23% prevalence of CWD in white-tailed deer. The disease also has been detected in 14 elk from a free-ranging herd of approximately 700 animals. These findings indicate that CWD has occurred in Arkansas for an extended period of time and became highly endemic prior to being detected in the state. This serves as a cautionary tale to the challenges of long-term, strategic surveillance, the reality of resource limitations, and the risk of complacency.
1:30PM CWD Management Strategies
  Mary Wood
Current data suggests that CWD is negatively impacting free-ranging cervid populations; however, sustainable management for CWD remains uncertain. To date, there has been little published information on effective CWD management, despite significant increases in our understanding of this disease. Many early CWD management programs were prematurely terminated due to lack of early, measurable success, high personnel/agency costs, and lack of public support. This highlights the need for management strategies that include realistic goals, can be applied for extended time periods, and have sufficient public and constituent acceptance. Future efforts toward CWD suppression should focus on strategies that exploit or complement current management activities. This may include strategies that alter or optimize harvest to enhance the efficacy of harvest as a control tool. Additionally, programs to reduce areas promoting artificially high cervid congregation that may serve as sources of prion concentration and transmission should be considered. Due to the complex sociopolitical aspects of CWD and limited information on effective management; no single jurisdiction is likely to be successful in identifying and implementing long-term CWD management alone. A regional, coordinated, adaptive management approach to CWD management may provide a path forward.
1:50PM Mitigating the risks of movement of CWD prions.
  Kelly Straka
Part of the challenge with the management of CWD is an incomplete understanding of transmission pathways and risk factors for prion transport. Many studies are based on proof of concept, and their translation to field applications is unknown. Wildlife managers are nonetheless faced with making decisions in the absence of scientific certainty, and must rely on the best available data at the time. This presentation will give an overview of possible methods of prion transport based on research findings to date, as well as transmission routes suggested by epidemiologic investigations. Management recommendations to mitigate the risks of prion transport, and outreach resources for interested stakeholders will be shared.
2:10PM Public Health Considerations Related to Chronic Wasting Disease
  Ryan A. Maddox; Jennifer House; Lawrence B. Schonberger; Ermias D. Belay
Background. Twenty-three states have identified chronic wasting disease (CWD) in free-ranging cervids; eleven of these states first reported the disease since 2009. As CWD spreads, the opportunities for human exposure increase. Although no strong epidemiologic evidence for transmission of CWD to humans exists to date, results of some animal studies are worrisome as is the recent outbreak of variant Creutzfeldt-Jakob disease associated with bovine spongiform encephalopathy. These factors support the advisability of developing appropriate public health guidance related to CWD. Purpose. To describe considerations related to public health guidance aimed at reducing human exposure to CWD. Results. CWD-related public health guidance must be prepared with attention to those to whom it is targeted. Recommendations perceived as unnecessary or unattainable may be ignored or not adhered to consistently. The scientific rationale behind such advice should be presented in plain language that clearly explains what is known about risk; limitations of recommended actions, such as those associated with the results of CWD testing, should also be described. In addition, involvement of relevant stakeholders such as wildlife agencies when debating appropriate guidance is an important step to maximize compliance and ensure that recommendations are feasible. Access to CWD testing deserves discussion as a potential barrier to reducing human CWD exposures. Conclusion. Those crafting recommendations to hunters and others potentially exposed to CWD should balance the available scientific data with proposed actions that are practical, possible, and likely to be adopted.
2:30PM Refreshment Break
3:20PM Chronic Wasting Disease Policy Status and Needs
  Jonathan Mawdsley
This presentation will provide an overview of current policy proposals at state, federal, and provincial levels in the United States and Canada which would provide additional tools and resources for managing Chronic Wasting Disease (CWD) in wild and captive cervid populations, and will discuss the alignment of these proposals with priority policy needs for CWD management that have identified through surveys of state, federal and provincial wildlife biologists by the Association of Fish and Wildlife Agencies. Key policy needs that have been identified as priorities for CWD management by state, federal, and provincial wildlife managers include: improved funding mechanisms for agencies engaged in CWD surveillance, monitoring, and indemnification; increased funding for targeted scientific research that would help to resolve outstanding questions in areas such as disease diagnostics, epidemiology, and decontamination; and improvements to current regulatory structures governing CWD response and management at state, provincial, and federal levels. Mechanisms for advancing these policy improvements include legislative, regulatory, and voluntary approaches, each of which may be appropriate in certain contexts.
3:40PM Review of Chronic Wasting Disease Regulations for Cervids in North America
  Melinda Cosgrove; Lane Kisonak; Carol Frampton
Regulations concerning chronic wasting disease (CWD) vary widely between state and provincial jurisdictions. While oversight of privately-owned cervids falls solely on the agricultural or wildlife agencies in a few states and provinces, both agencies jointly manage privately-owned cervids in most states and provinces. Many states and provinces have restrictions prohibiting importation of live cervids from another state or province where CWD is endemic; however some states ban importation (or ownership) of all live cervids. Even with the ever present and increasing threat of CWD, a few states and provinces have no ban or restriction in place allowing free movement of live cervids across borders. In states and provinces where privately-owned cervids are legal, some level of post-mortem CWD testing is required. These requirements and the level of enforcement varies greatly. All states and provinces also perform some level of CWD testing of wild cervids, again to varying degrees. Through this testing more than half of the states and three Canadian provinces have detected CWD in either privately-owned or wild cervids. Baiting and feeding of wild cervids continues in many states and provinces. More states ban or restrict baiting rather than feeding, even though feeding extends the temporal scale that animals are congregating at unnatural food sites. Increased attention is being placed on the movement of cervid parts and carcasses across jurisdictional boundaries. Movement of potentially infected parts and carcasses increases the chance of CWD being introduced into new areas and more states and provinces are taking steps to reduce or ban these movements. Sound and consistent regulations and practices across all jurisdictions would reduce confusion among stakeholders, especially those hunting in states and provinces other than where they reside; reduce introducing CWD into new areas; and reduce the likelihood of disease transmission in areas where it currently exists.
4:00PM Optimizing the Contribution of Research to CWD Management
  Margaret Wild; Jennifer R. Ballard
Significant advances have occurred in recent decades to expand our knowledge of prion diseases yet effective management strategies remain elusive. These knowledge gaps limit our ability to clearly foresee the biological, social, and political impacts of chronic wasting disease (CWD) and to take the most appropriate steps to mitigate negative consequences on conservation, animal, and, potentially, human health. Therefore, best management practices for agencies responding to CWD include consideration of opportunities to incorporate research into their work. Research activities range from opportunistic collection of data to implementation of rigorous landscape-scale evaluations of management interventions. At minimum, consideration prior to initiating surveillance and response can identify important and opportunistic contributions that could be gained with minimal added cost or workload. Development of controlled study designs to evaluate management strategies is a high priority research need. Collaboration across jurisdictional boundaries can be used to compare data over broad geographic areas and otherwise magnify the impact of these studies to a broader spatial and temporal scale. Well-designed studies that test experimental manipulations and disease dynamics over long time frames (at minimum 5 years) and wide spatial scales, e.g., Before-After-Control-Impact studies, are critical to informing effective management practices. In addition to biological research, research to understand the human dimensions of CWD is critical to developing best management practices. Understanding the human component can have dramatic effects on the success, failure, and future of CWD management. Understanding how stakeholders’ attitudes, social norms, and behavioral intent inform support for management actions are critical for programmatic success. Management agencies are well-poised to support critical research to close knowledge gaps and move toward successful management of CWD. Best management practices for CWD include incorporating research whenever possible and using available resources in the most effective manner.
4:20PM CWD Surveillance, Management, and Control: Conclusions and Next Steps
  Colin Gillin; Margaret Wild; Jonathan Mawdsley
This symposium was organized to bring together the best science on Chronic Wasting Disease (CWD) presented by researchers and managers with direct experience in the topics presented. Cwd has affected North American cervids for over 50 years, leaving wildlife managers with unprecedented challenges and few definitive answers on how best to mitigate its continued spread and impacts to conservation. Continued and increased research on disease transmission and coordinated regulatory actions are needed to circumvent anthropogenic promotion of the disease. We have learned that surveillance, management, and control efforts are expensive and well beyond any state agency’s discretionary funding for typical disease outbreaks. Managers who develop a solid interagency plan and conduct effective surveillance are more likely to limit intrastate movement if the disease arrives on the hoof, in a carcass, or in a trailer. The most effective way to not move the disease is to ban movement of all live cervids both from the captive cervid industry and via agency-sponsored restoration translocations. Also, concentrating cervids through baiting, feeding and attractants will likely increase transmission and prevalence in infected populations. Once established, management of CWD becomes difficult and expensive. Landscape-scale research is needed to develop effective management techniques. State agencies will need to manage and control prevalence through adaptive management strategies and integrate human dimensions as part of disease mitigation through social science surveys, comprehensive communications plans, and increased stakeholder outreach. Many questions remain and require research on better prion detection and new diagnostic approaches, understanding pathogenesis of the disease, disease-host ecology, and susceptible species. Other management questions seek to answer the role of plants, soil and prion persistence in extending the period of contamination of environments and habitats. Implementing and improving best management practices based on new scientific findings are critical to successful disease management.
4:40PM Panel Discussion
 

 
Organizers: Tom Deliberto, National Wildlife Research Center, Fort Collins, CO; Colin Gillin, Oregon Department of Fish and Wildlife, Corvallis, OR; Jonathan Mawdsley, Association of Fish and Wildlife Agencies, Washington, DC; Krysten Schuler, Cornell University, Ithaca, NY; Margaret Wild, National Park Service, Fort Collins, CO
 
Supported by: TWS Wildlife Diseases Working Group; Association of Fish and Wildlife Agencies; American Association of Wildlife Veterinarians

Symposium
Location: Cleveland CC Date: October 9, 2018 Time: 8:10 am - 5:00 pm