B&C Position Statement - Chronic Wasting Disease

Situational Overview

Chronic Wasting Disease (CWD) is a highly contagious, always-fatal disease that affects cervids such as deer, elk, and moose. It is difficult to detect CWD in live animals because it can take more than two years after infection for an animal to exhibit observable behavioral or physical signs of illness. Additionally, the diagnostic tests currently available are not as accurate when samples from live animals are used, when compared to samples collected after the animal has died or been euthanized. There is no treatment or vaccine for CWD.  

Research indicates that CWD can contribute to localized population declines in heavily infected, wild cervid populations, and CWD continues to be detected in new wild cervid populations in new areas in North America. Since 1996, the disease has been detected in captive and/or wild cervid populations in more than half of the states in the U.S. and in several Canadian provinces. Past attempts to eradicate the disease have failed, and efforts to control CWD through early detection, herd reduction, localized culling, and other methods have had limited success. Consequently, CWD management goals for wild populations have shifted from eradication to containment by minimizing its prevalence (percentage of population infected) and slowing the geographic expansion of affected areas. 

Animals with CWD shed disease agents called “prions” that can be transmitted directly to healthy animals through contact or indirectly through contamination of the environment with subsequent exposure of susceptible cervids. Infected animals can shed prions during the prolonged incubation period before clinical signs are apparent.  Prions can be shed in saliva, urine, feces, and through decomposition of the carcass of an infected animal. Prions bind to soil and remain in the environment indefinitely, capable of infecting healthy animals for several years. 

In addition to the geographic expansion of CWD through the natural movement of wild animals, human activities have facilitated its spread to distant locations. Based upon data from state and federal agencies, the transportation of live, captive deer and elk between breeding facilities and game farms is likely the most significant human-associated factor contributing to the spread of CWD to new locations. Unfortunately, CWD transmission between wild and captive cervids can occur in either direction through fence-line contact, escape of captive animals, or ingress of wild cervids. Hunters, game processors, and taxidermists also may contribute to the spread of CWD through transportation of infected carcasses without proper disposal at their destination. Other human activities regarded as CWD risk factors include feeding and baiting, which can cause unnatural congregation of normally dispersed wild cervids, and increase opportunities for disease transmission. 

State fish and wildlife agencies are responding to CWD detection in different ways, with some taking aggressive actions and others adopting a more measured approach. Public awareness and participation of hunters also vary, with some denying the existence of the disease while others recognize it as a very real problem that must be addressed. As a result, wildlife agencies and CWD managers always face hurdles when new control strategies are implemented (e.g., wild herd reductions, depopulation measures and transportation bans, etc.) that impact or conflict with the interests of stakeholders, including hunters, wildlife watchers, and commercial game farms.

To date, there is no evidence that CWD is transmissible to people, nor have any cases of human infection been documented. However, current research has not ruled out the possibility, no matter how small, and public health experts recommend that people avoid exposure to CWD by not eating animals that test positive and not eating animals that appear sick for any reason. 

As the nation’s oldest hunter-conservationist organization, the Boone and Crockett Club is deeply concerned with wildlife health issues, especially those that can have a negative and widespread effect on game populations. Sustainable game populations are key to public hunting, and hunters—through license/tag fees and excise taxes on hunting equipment—generate the primary source of funding for our system of wildlife conservation. 

Position

The Boone and Crockett Club maintains that CWD is a significant wildlife health problem that has the potential to prevent heavily infected populations of wild deer, elk and other cervids from thriving in the long term. The Club strongly encourages science-based surveillance and management practices to detect CWD early while few susceptible animals are infected, determine the extent of infection, and take rapid and aggressive steps to remove them from the landscape. In situations where the disease has become established, efforts should focus on containment and control strategies to keep CWD prevalence at low, sustainable levels.

The scientific community has answered many of the questions about CWD biology and ecology, but the knowledge needed to develop effective management and control strategies remains incomplete. How we address diseases among species like wild cervids that have continent-wide distributions is challenging, yet vitally important to the long-term sustainability of these populations. CWD management is complicated by several factors including the prolonged incubation period, lack of a practical live animal test, ability of the CWD agent to withstand typical heat or chemical decontamination treatments, and environmental persistence of the infectious prions. Containment also is complicated by the presence of CWD in captive and wild populations that can interact and infect one another. The transportation of live cervids will continue to pose significant risks to both wild and captive animals in the absence of strict regulations governing such practices. 

States, provinces, and tribal lands that are currently CWD-free should consider employing all available science-based, preventive practices to keep the disease from crossing their borders. Additionally, more should be done to understand and quantify human exposure risks. Efficacy of various management techniques intended to contain and control the disease should be rigorously evaluated and field-tested over timescales relevant to the disease’s life cycle.

The Boone and Crockett Club strongly encourages governmental authorities, as well as scientists, wildlife management specialists, and stakeholders, to collectively foster and develop sustainable approaches and initiatives to prevent, detect, monitor, control, and contain CWD. The Club supports the conclusions and recommendations of the Association of Fish and Wildlife Agencies (“AFWA”) in Resolution #2018-02-07 and an associated document containing Best Management Practices for Prevention, Surveillance, and Management of Chronic Wasting Disease (BMP).

The Club joins AFWA in concluding the most effective way to prevent CWD introduction and establishment is to prohibit all human-assisted live cervid movements. The Club encourages states to adopt AFWA’s Resolution in a manner that is appropriate for their own jurisdictions, and to support the Fish and Wildlife Health Committee in developing further science-based recommendations regarding the implementation of the practices described in the BMP document.

The Club will contribute to research, outreach/education, and legislative efforts to reduce infection and transmission rates, fill in knowledge gaps to most effectively manage CWD, stabilize wild cervid populations, and protect people through three primary avenues: The Chronic Wasting Disease Alliance, of which the Club is a founding member, the Club’s William I. Spencer Conservation Grants Program, and the Club’s network of Boone and Crockett Wildlife Conservation Programs located at prestigious universities across the nation.