Pennsylvania this fall rolled out new regulations for hunters to mitigate the spread of a fatal disease that affects deer and elk, but the state still isn’t requiring testing before processing venison.

Chronic wasting disease is a contagious prion disease that attacks the nervous system and often leaves deer with holes in their brain that cause death. There is no cure, and the only way to confirm an animal has it - sometimes called “zombie deer disease” - is through lab testing, which requires a sample from the brain stem or lymph nodes.

Studies have not shown the disease to be transmissible to humans, but the Centers for Disease Control and Prevention advises against eating infected meat.

The state first detected the disease in 2012 at a captive deer facility in Adams County. A few months later, three white-tailed deer in Blair and Bedford counties had it. Pennsylvania has reported nearly 1,300 chronic wasting disease cases across the commonwealth since the state Game Commission started tracking, a number that has increased annually.

Krysten Schuler, a wildlife disease ecologist at Cornell University, said the uptick could come from deer in areas with dense populations or from captive deer and elk herds at farms overseen by the state Department of Agriculture.

Prions - malfunctioning and almost indestructible proteins - cause chronic wasting disease, so disposal is key to mitigate further spread. Other prion diseases include Creutzfeldt-Jakob disease, which is rare but the most common that affects humans, and mad cow disease.

“If you had to design the perfect pathogen, prions are right up there,” Schuler told Spotlight PA.

Prions are durable, Schuler said. Extreme heat is most effective. Bleach can break them down, so hunters and processors should use it to clean their equipment for harvesting and handle high-risk deer parts with care.

Here’s what to know about how Pennsylvania handles chronic wasting disease, tests for it, and what happens to an animal that is found to have it.

Disease management area

Pennsylvania creates a disease management area after detecting chronic wasting disease, using a 10-mile radius buffer around each new confirmed case, Andrea Korman, a state biologist, said.

The Game Commission conducts road-killed deer surveillance year-round, so boundaries sometimes shift. The state Department of Agriculture also monitors deer and elk farms, conducting in-person inspections and reviewing annual inventory records.

The state has seven active disease management areas, which are predominantly located in rural counties.

It also has designated an “established area” that includes parts of Bedford, Blair, Franklin, Fulton, and Huntingdon counties. Almost 90% of positive cases of chronic wasting disease since 2012 have come from this region in the south-central part of Pennsylvania.

Hunting in these high-risk areas is permitted, but hunters must abide by special restrictions.

It is illegal to remove high-risk deer or elk parts - such as the head, spinal column, and spleen - from these designated areas unless hunters plan to take them to a state-approved cooperating processor. It’s also unlawful to dispose of these parts away from the harvest location, use the animal’s urine for attractants, or feed wild deer. Existing law already prohibits feeding elk.

Testing

Some hunters rely on the look and smell of the animal and its meat to detect issues, but testing is the only way to confirm if a deer or elk has chronic wasting disease, Schuler said.

Existing law doesn’t require hunters to test for the illness, but they can voluntarily submit their animal’s head to collection bins within high-risk areas during hunting season for free testing.

The Pennsylvania Animal Diagnostics Laboratory Systems also accepts deer harvested outside a regulated area for an $80 fee.

It takes about two weeks to get chronic wasting disease test results, but busier seasons extend the wait time, Korman said.

The game commission also collects samples from harvested deer collected at processors, road-killed deer within and around DMAs, and reported clinical suspect deer involved in other state programs, typically ones that look sick.

The state collects more than 11,000 samples each year, Korman estimated. During the 2022-23 deer session, hunters harvested about 423,000 white-tailed deer, which are abundant in the state.

Positive tests

If a deer submitted by a hunter tests positive for chronic wasting disease, the Game Commission can issue another tag as a replacement.

Handling parts of animals that test positive for chronic wasting disease is especially important because prions can seep into nearby soil and waterways if not disposed of properly, which could perpetuate the disease.

“The prion itself can last in the environment for a long time,” Schuler said.

Most things that kill bacteria, such as sunlight, won’t work on prions. Bleach can break them down, which is why meat processors and hunters should clean their equipment with it, she added.

While incineration is probably the most effective way to handle prions, most contaminated parts end up in landfills, which are typically lined with clay to prevent leaks, Schuler said.

That’s where the game commission sends high-risk parts, Korman said.

Food

The CDC cautions against eating meat from an animal with chronic wasting disease and urges people to test first.

There isn’t direct evidence of people getting chronic wasting disease, but there are confirmed mad cow disease cases in humans.

This story was produced by the State College regional bureau of Spotlight PA, an independent, nonpartisan newsroom dedicated to investigative and public-service journalism for Pennsylvania. Sign up for our regional newsletter, Talk of the Town. Spotlight PA is funded by foundations and readers like you who are committed to accountability and public-service journalism that gets results.