Since 1997, Wyoming Game and Fish has monitored the distribution and prevalence of CWD to better understand how this disease affects the health of Wyoming’s deer and elk populations. Continued monitoring of CWD over time is important to help Game and Fish understand the potential impacts of the disease as well as evaluate management actions for deer and elk.
Initial surveillance goals focused on monitoring the spread of CWD to new areas of the state. This disease has now been detected in most deer hunt areas across Wyoming.
Beginning in 2019, a surveillance regime was implemented that focuses sampling efforts on specific deer and elk herds in each Department region on a five-year rotational basis. The goal is to test at least 200 samples from adult elk (both sexes) and 200 samples from adult mule deer bucks harvested in each herd.
Bucks are targeted because Wyoming’s conservative mule deer hunting seasons result in primarily antlered deer harvest. The 200-sample goal allows wildlife managers to determine a statistically-valid prevalence estimate.
The herd unit rotation is designed to obtain prevalence estimates for each herd unit every five years to track trends over time.
It can take up to three years to obtain the 200 sample goal depending on the amount of harvest in a given herd unit.
Samples are collected during the fall hunting season through the cooperation of hunters who voluntarily allow Department personnel to collect lymph nodes from harvested animals at hunter check stations, in the field or at the regional Game and Fish office in Sheridan.
Below are results from samples collected between 2019 and 2021 from harvested adult buck mule deer, adult buck white-tailed deer, and adult elk.
The results show an estimated prevalence rate as well as the 95% confidence interval. A confidence interval provides a probability range, within which lies the true value.
For example, if a prevalence estimate is 15% with a 95% confidence interval of 10 to 20%, there is a 95% probability that the true value is between 10 and 20. In addition, prevalence rates can vary within herd units.
North Bighorn Elk Herd: This herd encompasses Elk Hunt Areas 35-40. Of the 219 samples submitted (adults of both genders), 11 samples were positive for a 5% prevalence rate with a confidence interval of 2-9%.
North Bighorn Deer Herd: This herd encompasses Deer Hunt Areas 24, 25, 27, 28 and 50-53. Of the 203 samples submitted from mule deer, 25 were positive for a prevalence estimate of 12% and a confidence interval of 7-18%. Of the 450 samples collected from white-tailed deer, 112 were positive for a 25% prevalence estimate and a confidence interval of 16-29%.
Upper Powder River Deer Herd: This herd encompasses Deer Hunt Areas 30, 32, 33, 163 and 169. Of the 231 samples submitted from mule deer, 43 were positive for a prevalence estimate of 18%, and a confidence interval of 12-20%.
Of the 38 samples collected from white-tailed deer, 18 were positive. Due to the small sample size we did not derive a prevalence estimate.
Powder River Deer Herd: This herd encompasses Deer Hunt Areas 17, 18, 23 and 26. Of the 540 mule deer samples submitted, 79 were positive for a prevalence estimate of 14% and a confidence interval of 10-18%.
Note: This herd was targeted for monitoring in 2019 and an adequate sample of 293 was obtained and reported on. At that time, the adult mule deer buck prevalence estimate was 11%.
Of the 158 samples collected from white-tailed deer, 60 were positive. Due to the small sample size, we did not derive a prevalence estimate.
Pumpkin Buttes: This herd encompasses Deer Hunt Areas 19, 29 and 31. Samples collected from mule deer are short of the 200-sample goal, but of the 170 samples collected, 24 were positive for a prevalence estimate of 14% and a confidence interval of 8-20%.
“Even though we did not achieve the goal of two hundred samples over three years, we will not target this herd for surveillance again until 2025,” said Stewart. “After assessing our efforts over the past three years and anticipated harvest in 2022, we do not expect that continued surveillance this year would be sufficient to reach that metric.”
Of the 28 samples collected from white-tailed deer, seven were positive. Due to the small sample size we did not derive a prevalence estimate.
“Sampling of white-tailed deer has not been consistent across hunt areas,” said Sheridan Wildlife Biologist Tim Thomas. “The majority of samples collected between 2019 and 2021 came from just three of twelve reported hunt areas. As we move forward and better coordinate sampling effort between the deer species, we should get better sample distribution across hunt areas.”
This year’s targeted sampling areas in northeast Wyoming are the South Bighorn Elk Herd, which encompasses Elk Hunt Areas 33, 34, 47-49 and 120 and the Black Hills mule deer herd which encompasses Deer Hunt Areas 1-6.
WGFD asks that if you harvest an elk, mule deer or white-tailed deer in one of these hunt areas, please submit a sample for testing to help achieve our goals.
Personnel who make contact with hunters in the field, at game check stations and at meat processing facilities will request CWD samples from harvested animals from these targeted areas. Sampling takes just a few minutes and requires removing a set of lymph nodes from the neck of the animal.
Participation is voluntary, but hunters are very important in helping Game and Fish understand the disease and achieve CWD monitoring goals.
Hunters harvesting deer or elk outside of this year’s focused surveillance areas can still submit a sample for testing by bringing their animal to an open checkstation or the Sheridan Regional Office.
In previous years, hunters who submitted a sample that detected CWD, received a written letter with the results. Beginning this year, results will be available online only. Hunters can look up the results of the test in 10 to 14 days via their Game and Fish account. The results will state whether CWD was or was not detected in the sample.
Animals infected with CWD can look healthy and in good condition. They usually do not show visible signs of the disease until the final few weeks of life. Therefore, a laboratory-tested sample is necessary to determine if the animal has the disease.
To date, there have been no cases of CWD in humans and no direct proof that humans can get CWD. However, animal studies suggest CWD poses a risk to some types of non-human primates, like monkeys, that eat meat from CWD-infected animals. These experimental studies raise the concern that CWD may pose a risk to humans and suggest that it is important to prevent exposures to CWD. Therefore, the Centers for Disease Control and the World Health Organization recommend that CWD positive animals not be consumed.
You can quarter and freeze your animal until test results are available to save on meat processing costs in case your animal tests positive. In the case of a positive CWD result, the lab results can be used as a receipt to dispose of the carcass at an approved landfill without the disposal being considered waste of edible parts.
As in past years, a hunting gear raffle is being offered to incentivize hunters to submit CWD samples from their harvested animal and to recognize the frontline role hunters play in battling this disease. Hunters will be entered to win prizes if they provide a usable CWD sample(s), with complete and accurate hunter and harvest information, from the appropriate tissue.
When hunters submit samples from adult male mule deer at least two years old, or any adult elk at least two years old from targeted CWD monitoring hunt areas, they have a chance to win Tier I prizes. Those targeted hunt areas are:
Deer: 1-6, 59, 60, 64, 65, 66, 124, 130, 131, 134, 135, 138-146, 150-156, 157, 165, 171
NOTE: Deer Hunt Areas 59, 60, 64, 65, 157, 171 require mandatory lymph node submissions for testing. Areas 157 and 171 are mandatory for mule deer AND white-tailed deer samples.
Elk: 7, 19, 33, 34, 41, 45, 47-49, 67-71, 75, 77-85, 88-91, 93, 95, 96, 102-105, 120, and 127.
Hunters could win Tier II prizes when they submit samples from all other deer, elk or moose for all other areas (non-targeted CWD monitoring areas) of the state, regardless of the hunt area.
First place: Browning Western Hunter Long Range Rifle (.300 PRC) with Recoil Hawg muzzlebrake AND Leupold VX-5HD 3-15x44 riflescope
Second place: Weatherby Vanguard High Country Rifle (.308) AND Maven RS.1 2.5-15x44 riflescope
Third place: Maven S.1S 25-50x80 spotting scope
First place: Weatherby Vanguard Weatherguard rifle (.25-06)
Second place: Maven B.1 10x42 binoculars
Third place: Stone Glacier Approach 2800 backpack, with XCurve Frame, medium hip belt