It was not that long ago that we heard about chronic wasting disease (CWD) occurring somewhere out west, but never considered that it would ever become a concern within our own borders here in Pennsylvania. Initially, reports were of limited outcroppings of the disease in deer and elk in a few of the western states, but that has all changed as the disease has slowly marched eastward and has gained a foothold in our state.
The precise location and first occurrence of CWD is not known, but the disease was first noted in 1967 in research mule deer herds in Colorado. By the late 1970s, CWD was recognized in captive facilities in Colorado and Wyoming in mule deer, black-tailed deer and elk. In 1981, the disease was identified first in the wild in elk in Colorado, followed by mule deer in 1985 in both Colorado and Wyoming. CWD spread to captive herds in Saskatchewan, Canada in the mid-1990s, then to wild cervids by the year 2000.
In 2001, CWD was identified in white-tailed deer in South Dakota wild herds and in a captive herd in Nebraska. In years following, the spread reached Minnesota, Wisconsin, New Mexico, Utah, Illinois, Kansas, Virginia, North Dakota, Iowa and finally reached Pennsylvania in 2012. Today, CWD has been reported in white-tailed deer, mule deer, moose, elk, and black-tailed deer.
Most cases of CWD occur in adult animals, are progressive and are always fatal. Initial signs of the disease are difficulties in movement, lowered head or lowered ears, rough coat and an obvious and consistent weight loss over time. Excessive salivation and grinding of the teeth has also been observed. Increased drinking and urination happens, which may contribute to the spreading of 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 is able to 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 suspect CWD positive animal.
Since its initial discovery in Pennsylvania in 2012, the numbers of reported cases of CWD have 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. DMA’s (Disease Management Areas) have been established to monitor the progress of the disease. As of March 2020, a total of 460 free-ranging deer had tested positive for CWD in Pennsylvania, 452 of them in DMA 2 (located in southcentral Pennsylvania) and the remaining 8 in DMA 3 (located in northwestern Pennsylvania).
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 also is prohibited within DMAs.
While we once looked at CWD as 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 good news, at the moment, is that CWD has not yet been detected in Lycoming county or any of the adjoining counties.
Please review pages 61-64 of the current Pennsylvania Hunting and Trapping Digest regarding the latest information about CWD in Pennsylvania.