Five Michigan DNR workers contracted tuberculosis, likely from testing deer

Five workers at Michigan’s Wildlife Disease Laboratory have been diagnosed with tuberculosis, possibly linked to “human error” as the lab struggled to test thousands of deer for chronic wasting disease, a Bridge Magazine investigation found. 

The Department of Natural Resources — which has made no public announcement — confirmed the TB cases in response to inquiries from Bridge Magazine this week. The infected workers have undergone several months of antibiotic treatment, and hundreds of other DNR employees were offered testing. 

The outbreak, the first of its kind at the 10-person lab, was diagnosed last summer. Workers at the lab were conducting tests on thousands of deer in search of two challenging diseases: chronic wasting disease and bovine tuberculosis, which is commonly found in cattle but also in deer and other animals. 

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The state theorizes the workers likely contracted the disease from white-tailed deer with bovine TB, according to state records Bridge received through a public records request. Almost 36,000 deer were tested for the disease in 2018, about 12,500 more than the year before.

State lab workers have raced to test deer as part of an effort to contain chronic wasting disease (CWD) after a so-called zombie deer was identified near Lansing in 2015.

“In 2019 – after we became aware of the [TB] infections – we scaled back the number of deer tested, in addition to reducing the hours employees were working during any given day at the lab,” DNR spokesman Ed Golder told Bridge in an email Wednesday.

“It’s conceivable the increased volume in 2018 led to human error or some other problem [that led to human infections]. We’re not certain,” Golder wrote. “Reviews by external agencies … weren’t able to draw any definitive conclusions about the cause of the infections.”

A DNR lab supervisor said it remains unclear what if anything the workers did, or did not do, that left them vulnerable to infection. 

“There was no documented incident. There wasn’t anything we could pinpoint. There wasn’t anyone who did anything wrong,” lab supervisor Kelly Straka told Bridge. “I can tell you that it has never happened before” in her career. “As someone who cares about their staff, it is upsetting.”

Bovine TB is a bacterial disease that primarily affects cattle, but deer in a northeast area of the Lower Peninsula have also contracted it. The disease, similar to human TB but more infectious, commonly involves the lungs and can lead to death. Bovine TB is also known to infect people, but deer-to-human transmission is extremely rare.

The five lab workers were diagnosed with a “latent” form of TB which can lie dormant for years and is not infectious to others unless it becomes active, which may never happen, DNR officials said.

The state never announced the cases publicly. In fact, DNR records obtained by Bridge suggest the department was keen on keeping the outbreak quiet. One DNR supervisor was threatened with punishment after he told a hunting group about the cases, according to personnel records obtained under the state Freedom of Information Act.

DNR supervisors issued a “notice of formal counseling” to Upper Peninsula wildlife supervisor Terry Minzey after he told a hunting group of the TB cases last summer. 

Minzey was accused of “sharing both inaccurate information and information without authorization” at an Aug. 10 meeting of the Upper Peninsula Sportsmen’s Alliance in Skandia, near Marquette.

“It is expected that at Division and Public meetings you share only accurate and authorized information,” deputy DNR chief Shannon Hanna wrote Minzey in the document, dated Oct. 16. “Failure to comply with this direct order may result in disciplinary action.”

Minzey objected to the findings. In his response, he said most of the information he provided to the hunters came from a widely distributed email to supervisors sent on July 9 to Wildlife Division staff.

“This was distributed to more than 200 employees and not marked confidential,” Minzey wrote. “There was no investigation conducted. I was never presented with the charges nor given an opportunity to respond to these charges.”

Two previous job evaluations obtained by Bridge rated Minzey as “high performing,” and praised him for being attuned to the political dimensions of DNR’s work.  

“He always keeps the Chief and I informed of what is going on in the U.P. that may or may not end up causing problems in Lansing,” then-deputy chief Steven Chadwick wrote in 2017.  

Golder, the DNR spokesman, would not comment on the action taken against Minzey, except to say, “We don’t discuss personnel actions, but I believe you have Terry’s records.”

Golder also said it was not necessary for DNR to publicly announce its lab workers had contracted tuberculosis because there was no infection threat to others and DNR wished to protect employees’ private health information.

“This is a small work group,” Golder said. “Revealing that there is an infection for any individual in that group will lead to questions for everyone in that small group.”

Transparency, or the lack of it, has been a problem for the DNR recently.

A Bridge investigation published in November showed that DNR leaders blocked the release of documents for years that contradicted the department’s rationale for killing federally protected gray wolves. 

State workers offered TB testing 

Records show DNR sent an email to volunteers last summer offering them the same TB skin checks given to Wildlife Division staffers. Golder said he did not know how many responded and sought testing.

Lab staff are routinely given a baseline TB skin test, then retested about six months after each deer season. Three staffers were identified as contracting TB last June and two more later in the summer.

All had negative follow-up chest X-rays and no symptoms, Golder said, indicating that their TB was inactive. DNR cautioned that it’s not known to a certainty the workers’ tuberculosis was actually contracted from the deer, given its dormancy. 

“There are no cultures to test,” said Straka, the lab supervisor. 

But the lab’s heavy workload in trying to identify and contain chronic wasting disease in Michigan deer is suspected as having played a role, according to the email to volunteers sent by a lab scientist, Melinda Cosgrove.

“There is no way to pinpoint exactly when or how the exposure happened,” Cosgrove wrote. “However with the increased testing demands and extended staff hours, it is possible that the exposures are a result of exceeding the capacity of our laboratory infrastructure.”

The wildlife lab tests for a range of animal diseases. Hunters submit the heads of deer they have killed to be tested for bovine TB and CWD. Lab workers typically wear protective clothing, including masks, goggles and respirators in some situations.

“We have added additional precautions that go above the typical protocols at this level of work, such as wearing respirators for all necropsies,” Golder said in an email. 

The DNR has also reduced the “volume of deer moving through the lab,” he added. Deer testing was cut by more than 10,000 animals last year, to about 25,000, because of the positive TB tests, Golder said.

The governor’s budget for next year seeks $300,000 to cover increased lab costs and $2 million in one-time funding for CWD research. 

Michigan is the only state where bovine TB is endemic, meaning it can survive indefinitely at low levels in a species. Almost all infected deer have come from 570 square miles in the northeast Lower Peninsula dubbed “Club Country” for the large number of private hunting ranches.

The deer management unit encompasses the four corners where Montmorency, Oscoda, Alpena and Alcona counties meet. Nearly 80 percent of TB-infected deer are from there, the DNR says.

Last year, more than 3,000 deer were tested from the four counties; 29 cases were found, about the same as the year before. No incidences of bovine TB in deer were detected in Michigan’s other 79 counties.

There have been 77 cattle herds found contaminated since the first herd was identified in 1998. The most recent was in January in Alcona County.

Underscoring the rarity and seriousness of deer-to-human transmission, the U.S. Centers for Disease Control and Prevention identified just three known cases in a study it published last fall. All involved hunters in Michigan since 2002, confirmed by genetic testing of some 900 deer samples collected by the state beginning in 1995.

One was a 77-year-old hunter in northeast Michigan whose active TB in 2017 was linked to a strain circulating in deer where he lived a decade earlier. 

Two previously known cases — in 2002 and 2004 — were more solidly confirmed in the same genetic study. One hunter had a cut finger while cleaning the deer; another is believed to have inhaled microscopic particles from an infected deer while field dressing the animal.

Dr. Laura E. Power, an epidemiologist in the School of Public Health at the University of Michigan and co-author of the study, told Bridge these earlier cases highlight clear genetic proof of deer-to-hunter transmission.

Power said DNR lab workers are at much higher risk than hunters.

“They are around zoonotic threats all day long,” Power said. “You don’t want panic. This is still very uncommon.”