Chronic Wasting Disease (CWD) was first noted in 1967 in research on mule deer herds in Colorado. By the late 1970s, it was recognized in captive facilities in Colorado and Wyoming in mule deer, black-tailed deer, and elk.
In 1981, the disease was first identified in the wild in elk in Colorado, followed by mule deer in 1985 in Colorado and Wyoming. CWD spread to captive herds in Saskatchewan, Canada, in the mid-1990s, then to wild cervids by 2000.
In 2001, CWD was identified in white-tailed deer in South Dakota wild herds, and in a captive herd in Nebraska. In the years following, the spread reached Minnesota, Wisconsin, New Mexico, Utah, Illinois, Kansas, Virginia, North Dakota, and Iowa and finally reached Pennsylvania in 2012. Today, CWD has been confirmed in at least 30 states and four Canadian provinces. Today, it has been reported in white-tailed deer, mule deer, black-tailed deer, caribou, moose, and elk.
Most cases of CWD occur in adult animals, are progressive, and are always fatal. Initial signs of the disease are difficulties in movement, followed by an obvious and consistent weight loss over time. Excessive salivation and grinding of the teeth have also been observed. Increased drinking and urination happen, which may contribute to spreading the disease.
CWD is caused by a prion — an abnormal form of a normal protein that is most commonly found in the central nervous system but can spread to the peripheral nervous system, thus infecting meat, or muscle, of deer and elk. Research indicates that prions can be excreted by deer or elk and are transmitted by eating grass growing in contaminated soil. An infected deer’s saliva can spread the CWD prions; thus, exposure between animals is associated with the sharing of food and water sources contaminated with CWD prions shed by diseased animals.
Hunters are advised to use standard precautions around animals, such as shooting only healthy-appearing animals, wearing rubber gloves for field dressing, and washing hands and forearms thoroughly. When processing the carcass, wear rubber or latex gloves and eye protection. Avoid cutting through the skull or spinal cord and use separate dedicated knives, saws, and cutting boards for butchering deer.
Although no current evidence links CWD to human health, it is recommended that people do not consume, distribute, or donate for human consumption a known or suspected CWD-positive animal.
Since its initial discovery in Pennsylvania in 2012, the number of reported cases of CWD has been increasing. In 2016, 25 free-ranging deer were positively identified as infected with CWD. In 2017, 78 free-ranging deer were detected in Pennsylvania — more than three times the previous year.
Seventy-five of the free-ranging positives were either within or near the boundaries of Disease Management Area 2 (DMA 2) in southcentral Pennsylvania, and the other three were within or near DMA 3 in northwestern Pennsylvania. DMA 4 has been added in the Lancaster County area to help combat and monitor the spread of CWD. Today, we are up to DMA 7, which is, unfortunately, in the southeastern part of Lycoming County and portions of surrounding counties to the east and south.
Currently, it is illegal to feed deer within the DMAs. Hunters are prohibited from transporting high-risk deer parts (generally the head and backbone) from deer they have taken within a DMA to points outside the DMA. Further, the use or field possession of urine-based deer attractants is also prohibited within DMAs.
While we once considered CWD a problem that only occurred “out west,” it has taken a foothold within our state and continues to spread. As sportsmen, we must pay close attention to this threat and comply with current regulations to do our part in helping stem the expansion of this disease.
Take time to become familiar with the signs the infected animals display and use common sense precautions in handling any animal or carcass that might be CWD-positive.
The task of hunters in the fight against CWD is to slow the spread and help buy time for science to find solutions. Researchers recently announced that they tested an experimental CWD vaccine based on a new understanding of CWD prion structure and produced a measurable immune-system response in elk. The next testing phase will involve whitetails and will begin in 2024.
It is critical that each of us, whether we are hunting out west or staying within the confines of Pennsylvania, learn as much as possible about CWD and what it means to the future of deer hunting. Please refer to pages 31-33 of the current Pennsylvania Hunting & Trapping Digest for a comprehensive presentation of the regulations regarding CWD in our state.
