Donated Iowa venison isn’t tested for protein that kills deer

By: - December 1, 2022 3:28 pm

Iowa's first shotgun deer season starts Saturday. (Photo courtesy of the U.S. Department of Agriculture)

The Iowa Department of Natural Resources recommends that all hunters test their deer for chronic wasting disease before eating the animals’ meat, but it does not yet require any testing for venison that is donated to food pantries.

The ailment is fatal for deer and is caused by an abnormal protein that destroys nerve cells over the course of years. The chronic wasting proteins can be present throughout the animals’ bodies, even in growing antlers. That means that humans who eat infected deer can consume the renegade proteins, which are not killed by cooking — they have notorious longevity in the environment.

There is no research that shows humans can contract the disease by eating tainted deer meat, yet the U.S. Centers for Disease Control and Prevention recommends against consuming it.

“Ultimately, the lack of evidence for risk to people today does not preclude the potential risk that may occur in the future,” said Tyler Harms, a DNR wildlife research biometrician who tracks the spread of the protein in Iowa.

But applying that same safety standard to deer that have been donated by hunters for the state’s Help Us Stop Hunger program — or HUSH — hasn’t happened.

A misfolded protein

Chronic wasting disease was first identified in captive deer in the 1960s at a research facility in Colorado. It spread to wild deer by 1981 and has since been discovered in more than two dozen states.

The disease is believed to be caused by misfolded proteins that encourage other proteins in the brain to become misshapen, leading to the destruction of nerve cells.

It affects deer, elk and moose and was first discovered in northeast Iowa in 2013. Until last year — when it was found in Greene County in the central part of the state — the disease had been detected in counties that border other states with known infections.

The DNR now samples about 6,000 deer per year that are killed by hunters or by vehicles, or those that show signs of the illness. Infected deer with advanced stages of the disease can have: weight loss; increased drinking, urination and salivation; and a lack of fear of humans.

Harms said it can take up to two years for deer to exhibit those signs of infection.

“A deer that is infected and is in the pre-clinical stage can still be infectious and look perfectly healthy and therefore not be displaying any of these clinical signs,” he said. “And so that’s what makes managing and detecting this disease on the landscape very important. And detecting this disease on the landscape can be very challenging, because again, most of the deer that have tested positive in Iowa to date have appeared to be normal.”

That testing has found 165 deer with the disease in Iowa so far in 12 counties. The areas with the greatest concentrations of the disease include counties in far northeast Iowa and Wayne County in far southern Iowa.

Research in Wisconsin — where more than 10,000 infected deer have been identified — has shown that older deer in a heavily contaminated county have about a 50% chance of carrying the disease, Harms said.

That’s partly because the proteins have been found to be infectious in the environment for years. Deer shed the abnormal proteins — known as prions — in their feces, saliva and urine. Male deer are more likely to be infected because they have more contact with other deer, and infected mothers can pass it to their offspring.

Testing is key

Sampling the lymph nodes of Iowa deer is a crucial aspect of tracking the spread and prevalence of chronic wasting disease in the state.

It’s also a measure that other Midwestern states have employed to ensure donated venison for food pantries is safe to eat.

In Missouri, deer that are felled by hunters in nearly 40 counties must undergo testing for the disease before they can be used for the state’s Share the Harvest program, which is akin to Iowa’s HUSH program. In Minnesota, deer that have been tested must be held aside by processors until results reveal whether they were infected. Meat from one deer is often comingled with others when it is processed into ground venison for distribution to food pantries.

How to test your deer

Hunters who want to want to have their deer tested for chronic wasting disease can contact their local DNR wildlife biologist.

They also have the option of removing the deer’s lymph nodes and sending one to the Veterinary Diagnostic Laboratory at Iowa State University.

There are no immediate plans to implement similar testing in Iowa.

“There’s nothing set in stone for it to be something that is required,” said Stephanie Lawrence, who oversees the HUSH program.

That program relies on a network of local meat lockers to process the donated deer.

“It’s just an extra step that they would have to go through,” Lawrence said. “It’s something that we would have to work with lockers to determine if that’s something that would be able to have done.”

The testing costs about $25 per deer through a DNR agreement with the Veterinary Diagnostic Laboratory at Iowa State University. It can take weeks to get results, which has the potential to create an untenable backlog of carcasses for some lockers. Most of the hunter-harvested deer in Iowa come from the state’s two shotgun seasons. They run from Dec. 3 to 7 and Dec. 10 to 18 this year.

Although chronic wasting disease has not been shown to affect humans, studies suggest it can infect monkeys, according to the CDC. It might be years before researchers determine whether there is a threat to humans.

“Nevertheless, these experimental studies raise the concern that (chronic wasting disease) may pose a risk to people and suggest that it is important to prevent human exposures,” the CDC said last year.

Todd Bishop, the DNR’s wildlife bureau chief, said the state would likely begin testing donated deer in the counties where the disease is most prevalent if it starts to require the sampling.

“It’s a difficult risk to assess right now because it’s not a known public health issue,” he said. “But we do pay attention.”

There are 30 state-approved HUSH lockers in Iowa this year, according to the DNR. They get paid per deer for processing. Maintaining or increasing that participation in the program is a consideration for imposing new requirements for donated venison, said Rachel Ruden, the DNR’s wildlife veterinarian. Some lockers have been wary of taking deer tested for chronic wasting disease due to liability concerns, she said.

But Ruden said the testing is an important consideration to safeguard donated food. Last year there were nearly 3,200 deer donated for the HUSH program.

“This is something that I, personally, am pretty passionate about, and it would not be out of line with what other states have done,” Ruden said.

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Jared Strong
Jared Strong

Senior reporter Jared Strong has written about Iowans and the important issues that affect them for more than 15 years, previously for the Carroll Times Herald and the Des Moines Register.