hronic Wasting Disease was first documented in the Sheridan Region of the Wyoming Game and Fish Department in 2004. Since then, extensive testing has confirmed the presence of the disease in nearly all of the region’s deer hunt areas and two elk hunt areas. No positive moose have been found in the Bighorn Mountains.
CWD is a chronic, fatal disease of the central nervous system in mule deer, white-tailed deer, elk and moose. CWD belongs to the group of rare diseases called transmissible spongiform encephalopathies. These disorders are caused by abnormal proteins called “prions.” The disease was first identified in free-ranging populations in the southeastern corner of Wyoming in 1985 and has since slowly spread north and west, now covering much of the state.
Continuing research indicates that CWD impacts to deer populations are measured in decades, not years. The disease cannot be eradicated as there is no effective vaccine or treatment at this time and there is no true genetic resistance. Spread of the disease occurs through animal to animal contact, but once the disease is present in an area, it persists in the environment where deer, elk and moose can become infected with the disease. For this reason, the WGFD has enacted regulations governing the transport of harvested deer and elk from any hunt area in Wyoming. WGFD regulations require the head and all portions of the spinal column to remain at the site of the kill or be disposed of in an approved Wyoming landfill. Hunters dumping skeletons of harvested deer, elk or moose along roadways, on public or private lands are potentially causing the spread of CWD, as well as littering and creating an unsightly situation that shines a bad light on hunters.
Much of what is known about where the disease occurs comes from the testing of hunter harvested deer and elk. Testing is also conducted on “targeted” deer and elk which are animals that are sick or in poor body condition. The WGFD CWD monitoring program is designed to assess prevalence and spread of CWD within deer, elk and moose populations. Testing of hunter harvested animals provides the most accurate assessment of prevalence rates. Although the disease has now been found to exist within most deer hunt areas within the Sheridan Region, prevalence rates remain relatively low at less than 10 percent in most hunt areas, compared to areas of southeast Wyoming where prevalence rates have been documented exceeding 40 percent. It does appear that prevalence rates have increased over time, as the disease has become established within deer herds. In the Sheridan Region, white-tailed deer appear to have a higher prevalence rate than mule deer, likely because of the high densities of white-tailed deer found in some areas. The WGFD will again be testing a limited number of deer, elk and moose during the 2017 hunting season to assess prevalence rates in local herds. Hunters who wish to have their harvested deer, elk or moose tested can do so at a hunter check station. Test results may take up to three weeks. Hunters wanting results within 10 working days can contact the Wyoming State Veterinary Lab in Laramie at 307-766-9925 and pay a $30 fee to have their animal tested.
There is currently no evidence that CWD is transmissible to humans, but it will take many years to accurately determine if humans can contract this disease. The Centers for Disease Control and the World Health Organization recommend that CWD positive animals should not be consumed.
For more information on CWD visit the Wyoming Game and Fish Department’s website at https://wgfd.wyo.gov/Wildlife-in-Wyoming/More-Wildlife/Wildlife-Disease/CWD-in-Wyoming-Wildlife.
Dan Thiele is a Sheridan wildlife management coordinator is the author.