UNIVERSITY PARK, Pa. -- The discovery this fall of chronic wasting disease in two deer on a game farm in southeastern Pennsylvania has hunters concerned, but they shouldn't overreact, according to experts in Penn State's College of Agricultural Sciences.
Because the disease -- often referred to as CWD -- was discovered in recent years in both wild and game-farm deer in the neighboring states of New York, West Virginia, Virginia and Maryland, the reality is it may have crept undetected into Keystone State deer from a number of sources, noted David Wolfgang, extension veterinarian and field studies director in veterinary and biomedical sciences.
Currently, more than two dozen deer farms remain under quarantine as part of the Pennsylvania Department of Agriculture's ongoing CWD investigation. So far, there has been no sign that the disease has crossed over from the captive deer population to the wild deer herd.
"Despite surveillance for CWD, it is possible that the disease may have been here for a while at a very low level and the testing program just didn't reveal it," Wolfgang said. "The Pennsylvania Game Commission has an aggressive, proactive testing program. The agency has tested between 3,000 and 4,000 hunter-killed deer around the commonwealth each year for almost a decade.
"But even with that level of testing, it is still possible, with the large deer population in this state, that at least a few infected animals may have gone undetected."
Chronic wasting disease -- a progressive disease of the nervous system always fatal to deer, elk and moose -- has been known to exist in Western states for nearly four decades, and it hasn't decimated the herds, as wildlife biologists feared, Wolfgang pointed out.
"Deer hunters have gotten used to living with it, and it hasn't ruined their sport or their health," he said. "They have developed a control and management strategy, and I think that's the attitude we should take with CWD here in Pennsylvania."
Although CWD is a fatal disease among cervids, research suggests that humans, as well as cattle and other domestic livestock, are resistant to natural transmission.
"While the possibility of human infection remains a concern, it is important to note there has never been a case of humans contracting CWD," he said.
"The disease, which appeared in Colorado in the late 1960s and has spread east and south since then into 22 other states, has not jumped between species."
When the malady -- which scientists theorize is caused by an agent called a prion, capable of transforming normal brain proteins into an abnormal form -- showed up more than a decade ago in Wisconsin, wildlife management officials in that state embarked on an aggressive deer-depopulation program and killed thousands of wild animals.
"But after spending millions of dollars to eradicate a massive number of deer and test hundreds of thousands of deer, they still have CWD in Wisconsin," said Wolfgang. "Once in the wild population it is much more difficult to eliminate.
"Now we have it on a Pennsylvania farm, and if we don't get good cooperation between deer hunters and deer farmers, we may find it difficult to eliminate here as well."
Perhaps most alarming to wildlife-management officials was the precipitous decline in the sale of hunting licenses in Wisconsin after CWD was discovered in that state, because hunters are the major tool used to control deer numbers.
"Hunting license sales in Wisconsin have returned to just about where they were prior to CWD," Wolfgang said. "We are encouraging Pennsylvania hunters not to overreact to the presence of CWD and not to change their way of life unnecessarily."
Catherine Cutter, associate professor of food science whose areas of specialty include the food-safety aspects of processing meat from deer and other wild game, echoed that sentiment.
"CWD does not present a food-safety issue," she said. "We have no reason to believe that the disease could affect humans -- CWD has not been linked to human illness -- but the U.S. Centers for Disease Control and Prevention does recommend against eating meat from deer infected with the disease."
With some common-sense precautions, hunters can protect their health and their family's health, Cutter stressed. "And hunters can be safe without going to a lot of trouble."
She advised hunters to observe the following basic precautions when handling deer carcasses:
-- Avoid butchering, processing or consuming venison from an animal that appeared sick in any way. "Steer clear of deer that appear emaciated or wobbly or display an unnatural lack of fear," she said.
-- Wear rubber or latex gloves when handling venison and processing deer. "That's a wise practice even if you aren't worried about CWD," she said.
-- Don't cut into the brain, spinal cord, spinal column or lymph nodes when butchering.
-- If possible, hang deer by hind legs with head down when butchering. "Most cattle and livestock processed in this country are hung with the head down," Cutter said. "That prevents brain and spinal fluids from contacting the meat."
-- Use a knife and debone all venison. "Cutting bone could expose meat to nerve tissue," Cutter said.
-- Once you are finished processing, clean all knives and utensils thoroughly with warm, soapy water, and then soak them for a few hours in a 50 percent solution of bleach and water. "Strong chlorine solutions have been shown to greatly decrease the infectivity of prions, the infectious agents of CWD found in the nerve tissue of infected animals," she said.
-- Properly dispose of brain, spinal cord, spleen, tonsils and other organs. "Appropriate disposal depends on what state you are in," Cutter explained. "In Pennsylvania, you should seal the remains in plastic trash bags and be certain they are disposed of in a lined landfill that is not exposed to runoff and doesn't leach into groundwater. That describes most municipal landfills."