A disease that is a threat to deer is gaining a bigger foothold in Pennsylvania.
Chronic wasting disease is a transmissible neurological disorder of deer characterized by loss of body condition, behavioral abnormalities and always the death of the animal. Neither bacterial nor viral, it is the result of an oddly folded protein, or prion, causing a form of spongiform encephalopathy that carves sponge-like holes in the brains of its victims, similar to mad cow disease in cattle and scrapie in sheep.
Originating in Colorado in 1969, CWD is now confirmed in 24 states including Pennsylvania, where it seems to have recently crossed a transmission threshold, doubling the number of cases from 2016 to 2017. It is not contagious to pets, but recent research suggests that despite longtime scientific consensus, it may be transferable to humans who eat the malformed protein.
CWD is a disease of cervids — hooved animals in the deer family — which are considered “keystone species” because they eat the habitat that every other animal needs for food and shelter. Researchers have said the rapid elimination of a keystone species in CWD hotspots would have dire consequences for all plants and animals and the people who enjoy them.
Chronic wasting disease was the subject of a well-attended seminar Sunday at the Allegheny Outdoors, Sport and Travel Show in Monroeville. Wayne Laroche, special assistant for CWD response for the Pennsylvania Game Commission, said the state’s fourth Disease Management Area will soon be established following a new case discovered on a commercial deer farm in Lancaster County last week.
“This is a setback here in Pennsylvania and it’s now in half of the states,” Mr. Laroche said. “Hunters know about this because they know what’s going on with deer, but for the most part the general public is just starting to hear about it now.”
The prions are believed to have spread through the commercial exchange of deer among deer farms from Texas to Saskatchewan province in Canada. Researchers including Mr. Laroche say spotty distribution in wild deer from the Rocky Mountains to south-central Pennsylvania suggests the prions are crossing deer farm fences and entering wild populations.
The misfolded proteins are resistant to an enzyme that breaks down proteins and peptides. The resistance is transferred when a prion touches a healthy protein.
Chronic wasting disease was first documented in Pennsylvania in 2012 at a deer farm in Adams County. Despite the immediate implementation of planned anti-CWD protocols, the disease was found months later in three hunter-killed deer in the south-central region.
By 2016, 47 CWD-positive deer had been discovered among wild deer in Pennsylvania. Last year, chronic wasting disease was confirmed in a wild deer 90 miles northeast of Pittsburgh within a disease management area adjacent to populations of Pennsylvania’s free-ranging wild elk, which are susceptible to CWD.
“[In 2016,] we sampled about 5,700 [deer] and ended with 25 [cases] outside of deer farms,” Mr. Laroche said. “This year, we took samples from about 8,000 deer. So far, the total number of new CWD positives in Pennsylvania is 55, but there will be more. We have more than 4,000 test results still outstanding.”
Vendors at the outdoors expo had mixed views on CWD. Scott Angelo of the Ohio Department of Natural Resources said CWD has affected only captive deer in the state and those that escape are euthanized. Last week, however, an escapee from Stark County could not be found.
“Some people think this is something that will burn itself out,” Mr. Laroche said. “They don’t want to think about it. People outside the hunting community haven’t shown interest because they’re not invested.”
He said all anti-CWD expenditures in Pennsylvania are paid using hunter dollars from license and permit fees and a federal excise tax on hunting equipment.
“The general public isn’t paying for it, so they haven’t noticed it yet,” he said. “But if this isn’t curbed it’s going to impact everyone.”
John Hayes: jhayes@post-gazette.com or 412-263-1991.
First Published: February 19, 2018, 3:25 p.m.
Updated: February 19, 2018, 3:25 p.m.
