DIY Science: Hunters Can Collect CWD Samples Themselves
Hunters who like DIY projects can expand their self-reliance by extracting the lymph nodes of deer they shoot and getting them tested for chronic wasting disease.
The Department of Natural Resources isn’t making a big deal about this do-it-yourself CWD option, so you won’t see public-service ads on billboards. Neither will you see famous hunters showing how to extract lymph nodes on YouTube videos.
The DNR is just trying to make CWD testing more convenient for hunters, no matter where they chase deer in Wisconsin. And by providing more CWD samples from across the state through citizen-science, hunters can help the DNR better monitor the disease.
Make no mistake: This isn’t a home-testing kit for CWD. After picking up a test kit from a DNR office or self-serve CWD kiosk, you’ll extract the two lymph nodes from the junction of the deer’s neck and head. Then you’ll place them in small bar-coded zip-lock baggies, fill out an information sheet, and drop off the kit with the DNR or at a CWD kiosk.
CWD has never been linked to its human equivalent, Creutzfeldt-Jakob disease, but the DNR and World Health Organization still recommend not eating venison from deer testing positive.
Since adopting a “passive” approach toward CWD as its policy in 2014, the DNR only monitors the disease through voluntary testing. Even so, 38 of Wisconsin’s 72 counties have had at least one wild deer test positive for CWD. Further, only 17 counties remain “unaffected” by the always-fatal disease. That means 55 counties either have CWD in wild or captive herds, or their borders are within 10 miles of a confirmed case.
CWD sampling has climbed the past five years through increased DNR efforts, with annual averages of 18,160 since 2018. Monitoring efforts nosedived the previous decade after the Legislature slashed the program in 2007, dropping the annual average to 7,222 samples statewide from 2007 to 2017. The current effort, however, still lags the 2003 to 2006 annual average of 22,290 tests.
Hunters in southern Wisconsin’s farmlands, where CWD is widespread and worsening, still provide the most samples. Of 17,138 deer tested statewide in 2021, 7,661 (45%) came from southern counties, while the state’s central farmlands delivered 6,636 (39%) samples, and the Northern forest 2,250 (13%).
Of the 2021 samples, 17% tested CWD-positive in southern counties. And although only 0.6% of central-farmlands samples tested positive, the region’s CWD cases more than doubled, rising from 19 in 2020 to 41 in 2021, even though hunters provided 24 fewer samples (6,660).
The DNR tests deer for CWD at no cost to hunters, and provides drop-off sites statewide (https://dnr.wisconsin.gov/topic/WildlifeHabitat/registersample.html). Even so, self-serve CWD kiosks and bone-disposal dumpsters aren’t convenient for everyone, especially in northern Wisconsin. Therefore, hunters who want their deer tested might prefer the DIY option.
Since CWD’s discovery during the November 2001 gun-deer season, few hunters have gotten their deer tested. For instance, of the nearly 1.6 million deer registered statewide during the 2017 through 2021 archery and firearms seasons, hunters only submitted 85,538 (5.4%) for testing.
A DNR survey of Wisconsin deer hunters after the 2019 season found 70% have never submitted a deer for testing. Further, only 9% submitted a deer for testing in 2019, and only 5% said they tested all deer they killed the previous five years.
Hunter-provided lymph nodes are typically extracted by DNR staff, trained volunteers at CWD drop-off sites, or taxidermists preparing clients’ bucks for mounting. The DNR doesn’t expect a big increase in CWD testing by do-it-yourselfers, but it’s a handy option for those immersed in the hunting experience, said Amanda Kamps, the DNR’s wildlife health specialist.
Kamps recommends doing your homework before “trying this at home.” Start by visiting the DNR’s CWD website, https://dnr.wisconsin.gov/topic/wildlifehabitat/cwd.html, and clicking the “CWD Sampling” tab to watch a video on how to find and remove the two lymph nodes.
The website also offers a printable 10-page tutorial with step-by-step instructions. In addition, the UW-Madison veterinary diagnostics laboratory, which tests all hunter-submitted samples for the DNR, offers a similar tutorial at this link: https://www.wvdl.wisc.edu/wp-content/uploads/2022/07/CWD-Submission-Instructions.pdf.
Kevin Wallenfang manages the DNR’s CWD processing center near Poynette. All hunter-provided samples pass through this facility, which is staffed by up to 16 DNR employees daily during Thanksgiving week and the following week, the peak time for samples taken during the nine-day firearms season.
Wallenfang, too, recommends watching and reading the agency’s how-to tutorials beforehand. “It can be a tricky job, even for experienced people,” Wallenfang said. “The lymph nodes can be different sizes and colors, and it’s easy to cut too far forward or too far back. In general, the sooner you extract them, the easier it is. Once the neck freezes or gets stretched when hung up, the job gets harder.”
A few tips:
-- Lay the deer’s head and neck out flat, ears down and throat patch up. If you have a pickup truck or trailer, lay the deer so its entire head extends out the back, exposing its neck.
-- Locate the ends of both jawbones and press on the larynx directly in between. You should feel a slight bump and small divot. Cut there with a sharp knife, making a slightly U-shaped slice rearward just past the jawbones’ ends, stopping at the spine below.
-- Grab the larynx and cut through, exposing the esophagus. The two lymph nodes sit in a pocket left and right of the esophagus.
-- The lymph nodes are firm and bean-shaped, unlike nearby salivary glands. Their tissue is dense, making them feel like grapes. If you poke or press them, they’ll retain their original shape. If you poke or press salivary glands, they’ll flatten out.
-- If you head-shot the deer, let DNR staff extract the lymph nodes. That bloody job requires expertise.
After the DNR sends lymph nodes to the UW-Madison laboratory, hunters can expect test results within a week or two. Daniel Barr, the university’s pathology sciences supervisor, said the lab is again at full strength after struggling to find qualified staff in 2021. The lab is also fully stocked with testing agents after enduring shortages last year.
“COVID-19 caused the same shortages of staff and supplies that many businesses experienced last year,” Barr said.
If you’re uncertain the samples you collect are good, freeze the deer’s head and upper neck until learning the test results. The DNR will contact you if your sample wasn’t viable.
Either way, CWD testing is growing increasingly convenient. If you can fillet a fish, skin a raccoon or cape out a buck, you can probably extract a deer’s lymph nodes.
CWD Samples Analyzed in Wisconsin
Year Samples Year Samples
2022 1,816* 2011 5,313
2021 17,138 2010 7,445
2020 18,916 2009 7,168
2019 19,368 2008 12,289
2018 17,216 2007 9,297
2017 9,900 2006 30,269
2016 6,137 2005 24,811
2015 3,147 2004 19,139
2014 5,472 2003 14,939
2013 6,671 2002 40,116
* Incomplete. Current sampling year continues through March 31, 2023.
Hunters no longer have to rely on DNR staff or trained volunteers to collect CWD test samples. They can now do the job themselves. — Patrick Durkin photo