Page 24 - MDWFP CWD Response Plan
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Appendix E ------ Eradication and Control Attempts

                   Many different strategies to combat CWD have been employed around the country with
                   varying levels of success. For disease eradication, early detection of CWD infected animals
                   is paramount. The time between introduction and detection of the disease is the most critical
                   factor impacting an agency’s ability to control and possibly eradicate the disease before it can
                   become established. Once the environment becomes a reservoir for CWD prions, mitigating
                   the spread of the disease may be the only reasonable course of action. Population reductions
                   may help reduce the dispersion of infected deer to non‐infected areas. Severe population
                   reductions within a reasonable area around the index case would likely be most effective in
                   scenarios where CWD appears to have been recently introduced and has not likely become
                   established in the environment (Brown et al. 2005). However, severe culling efforts have
                   been less popular in areas where CWD is well established, as hunters and the general public
                   eventually grow weary from the intensive culling practices that continue indefinitely.

                   Eradication Attempts – New York discovered CWD in two different captive herds during
                   routine CWD surveillance in 2005. They promptly initiated an intensive surveillance effort
                   within 10 miles of the infected premises, and confirmed CWD in two free‐ranging deer. It
                   appears that removal of those two deer at least temporarily prevented further spread of CWD,
                   as the disease has not been detected in any additional deer despite intensive sampling through
                   severe population reductions for the following five years (Brown et al. 2005). Intensive
                   culling also appeared to work in a similar situation in Minnesota, where CWD was confirmed
                   in a wild deer within three miles of an infected captive elk herd. Sharpshooters collected
                   almost 1,200 deer within the “Disease Zone” during the winter of 2011, and hunters provided
                   samples from 2,300 deer harvested during the following fall with no additional CWD
                   detected. It seems that the introduction of CWD into free‐ranging deer in Minnesota was
                   detected very early and establishment of the disease was prevented.

                   Control Attempts – However, in areas of Wyoming, Colorado, and Wisconsin where CWD
                   has been established for many years, eradication is an unrealistic management option. This is
                   likely the situation in the Hueco Mountains of west Texas, where limited sampling indicates
                   disease prevalence may average ~10% but may exceed 50% north of the Texas ‐ New
                   Mexico border.

                   In these situations, major population reductions would not prevent animals from contracting
                   CWD from the contaminated environment. In such situations, strategies to restrict or reduce
                   the movements of free‐ranging or captive cervids (and carcass parts) from CWD endemic
                   areas may effectively reduce the spread of CWD. Some states partner with hunters to help
                   monitor prevalence and distribution, as well as manage deer and elk populations to meet
                   CWD‐ management objectives. Several states, including Wyoming, also employ other
                   disease management strategies such as a ban on baiting, prohibiting unnatural (i.e., man‐
                   induced) movements of deer or carcasses, and general education efforts to encourage
                   responsible actions by hunters and other stakeholders.

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