By Doug Leier
Information and education are important components of the fight against chronic wasting disease, or CWD as it is often abbreviated. Ironically, shortening the identifier doesn’t give credence to the concern posed for deer species, big game biologists and wildlife managers.
The Game and Fish Department website is home to details about CWD and what follows are some of the high points to help all better understand the disease and a review of the high priority this issue takes with Game and Fish Department personnel.
What is chronic wasting disease?
Chronic wasting disease is a fatal brain disease of white-tailed deer, mule deer, elk and moose. It belongs to a family of diseases known as Transmissible Spongiform Encephalopathies (TSEs), or prion diseases. Although CWD shares certain features with other TSEs, like bovine spongiform encephalopathy (BSE or mad cow disease), scrapie in sheep and goats, and Creutzfeldt-Jakob disease (CJD) in humans, it is a distinct disease of deer, elk and moose. CWD damages portions of the brain, causing tiny holes that results in a sponge-like appearance when viewed with a microscope.
Where is it found?
Since it was recognized in Wyoming and Colorado several decades ago, CWD has spread to wild or captive deer and elk herds in 26 states and four Canadian provinces. It has also been found in South Korea and Scandinavia. CWD was first detected in North Dakota in a mule deer buck taken in the fall of 2009 in the southwestern part of the state. In 2018, it was found in northwestern North Dakota.
How common is it?
CWD can become quite common in a population after it is introduced into an area. For reasons that are not completely understood, the highest infection rates are often found in adult bucks. In some areas of the country where CWD has become well-established, over 40% of adult bucks are infected with CWD. The number of years it takes to reach these infection rates depends on several factors including local deer densities and biology, landscape features, and how aggressively CWD is directly managed.
Why is CWD a concern?
There are several reasons to be concerned about CWD. As infection rates increase, CWD can become the dominate, annual cause of mortality that threatens the long-term viability of a herd and impact how many animals can be sustainably harvested each year. The higher infection rates observed in adult bucks can also result in a shift to a younger age structure. While there is no direct evidence that humans can be affected by CWD, public health experts recommend that CWD-positive animals should not be consumed.
2021 Update for North Dakota testing
Eighteen deer tested positive during the 2020 hunting season. Fourteen were from hunting unit 3F2, two were from unit 3A1 and one was from unit 4B. A white-tailed deer harvested in unit 3A2 also tested positive and was the first detection in the unit. The estimated infection rates in unit 3F2 were 5.1% in mule deer and 2.2% in whitetail deer. It was less than 2% in other positive units. Approximately 7% of hunters turned in heads for testing in units where the Department was focusing surveillance efforts.
How to help
Hunters are the most important tool for managing CWD because they help keep deer herds at healthy densities while removing a portion of the infected animals from the landscape each year. Hunters can also help reduce CWD transmissions by observing carcass transportation restrictions, disposing of carcass waste via landfills, and moving away from the practice of baiting, regardless of whether CWD has been detected in an area. Nonhunters can also help by avoiding recreational feeding of wildlife and reporting deer that were found sick or dead of inapparent cause to the Department.
More information about CWD can be found at gf.nd.gov/cwd.
Leier is an Outreach Biologist with the NDG&F Dept.
Featured Photo: A white-tailed deer taken in 2020 from unit 3A2 was the first to test positive for CWD in that hunting area. NDG&F Photo.