The mysterious pathogen that causes chronic wasting disease (CWD) in deer can survive searing temperatures that would easily kill other infectious agents.
It can lurk for unknown lengths of time on rocks and in the soil, where it can be incorporated into the leaves of growing plants. And it is always fatal in deer, an animal that generations of Minnesotans have relied on to feed their families.
Although there have been no reported cases of CWD transmission from deer to humans, a pathogen causing a similar disease in cattle, often called “mad cow disease,” did make the leap to humans. Leading health organizations advise against eating venison from infected animals as research continues. A critical problem highlighted in a disturbing Minnesota legislative hearing last week is that there is no rapid field test to determine which animals have this degenerative brain disease, which is now present in “free-ranging deer, elk and moose” in at least 24 states, federal health officials say.
Minnesota is regrettably one of these states, and a solution is urgently needed. Fortunately, the state’s combined expertise in public health, veterinary medicine and nanotechnology puts it in position to develop a next-generation rapid and inexpensive field test. What’s needed is an assist from Minnesota lawmakers.
A soon-to-be introduced bill will seek $1.8 million to launch the test’s development. The legislation ought to set a speed record for passing the House and Senate. Separate legislation that provides additional dollars for the state Department of Natural Resources (DNR) to track the disease merits the same swift passage.
To be clear, testing is currently available for CWD in deer. In some areas of the state, generally southeast Minnesota, it is mandatory. But the process is not fast and not user-friendly, requiring specific tissue from deep within the deer. Nor can it be done on live animals, which poses significant challenges to track the disease among farmed deer and elk. Escaped or transported farmed animals are believed to play a role in CWD’s spread.
Since 2002, CWD has been detected in 18 wild deer out of about 64,000 tested in the state, according to the DNR. The agency has considerable information on its website for concerned hunters, including a helpful how-to video on cutting out the tissue needed for testing,
It also provides “drop boxes” to collect deer heads for testing in certain areas. And, the agency has worked to reduce testing costs (which start at about $18) and shorten the turnaround time for results, which can take months in other states but can be three or four business days for deer harvested in areas of heightened CWD concern in Minnesota.
Clearly, more improvements are needed. Rep. Jamie Becker-Finn, DFL-Roseville, will be the test development bill’s lead author. Her freezer, she said, is filled with about 90 percent venison. Along with other legislators, she posed difficult questions about feeding venison to families to the world-class scientists gathered for last week’s hearing.
Answering those questions is difficult for many reasons. While the rapid-response field test would help, it doesn’t resolve all of the concerns. A big unknown is whether the CWD pathogen — proteins known as prions — may linger on equipment in facilities where multiple hunters take their animals to be processed. Can this infect meat that comes from a healthy deer?
A phrase that stood out at Thursday’s alarming hearing was “We don’t have a test for that” — a statement made repeatedly by the University of Minnesota’s Dr. Jeremy Schefers as he outlined CWD’s many unknowns. Among them: How can these proteins move from soil and plants to animals, and what is the threshold amount needed to infect an animal?
If we are going to starting fight back against CWD, Schefers said, “We need better tests, plural.”
The nexus of health and technical expertise in Minnesota, coupled with weak leadership at the national level, requires the state to take the lead. The rapid-response field test optimistically would take about two years to develop. Let’s get the process started as soon as possible and, in the meantime, ensure that the DNR and other agencies have robust resources to combat the disease and boost awareness among Minnesota hunters.