Development of field test for CWD comes as its threat grows

Tom Cherveny, West Central Tribune, Willmar, Minn.
·4 min read

Apr. 23—A team at the University of Minnesota has developed a deployable field test for Chronic Wasting Disease that will greatly improve our ability to monitor the disease in the state's deer population.

Its announcement this week came along with sobering news of just how urgent the need is.

The development was announced on Monday by Dr. Peter Larsen, assistant professor in the Department of Veterinary and Biomedical Sciences at the University of Minnesota College of Veterinary Medicine and co-director of the Minnesota Center for Prion Research and Outreach.

He spoke to the Minnesota House Environment and Natural Resources Finance and Policy Committee on Natural Resources chaired by Representative Rick Hansen, DFL-South Saint Paul.

Larsen made clear the urgency of improved testing capabilities. CWD poses a direct threat to Minnesota's cervids, including whitetail deer, moose and elk. "We are at war. We are at war with an infectious prion protein," said Larsen. The misfolded prion that is the cause of this always-fatal disease to cervids can be transmitted from deer-to-deer and by exposure in the environment, where it can persist for years in the soil.

Current testing does not allow us to detect early stage infections in deer, Larsen told the committee. As a result, "we're always two or three years behind the enemy."

The new test, dubbed the MN-QuIC, provided results in about nine hours when field tested last March.

The field test is a straightforward process where a reactive agent will turn red for a positive result and blue for a negative.

In blind testing, the DNR provided tissue samples from 500 deer knowing that 12 in the mix were CWD positive. The new test identified the 12 positive samples and also identified four other potential infected samples that may have been missed by the conventional testing process, Larsen told the committee.

His presentation came after the recent news that the carcass of a captive deer in a cervid farm in Beltrami County had tested positive for CWD. This is the furthest north that CWD has been confirmed in the state. Its presence is linked to the movement of deer 370 miles from a cervid farm near Houston in Southeast Minnesota.

It now raises concerns about the disease reaching the wild deer population to an area affecting members of the Leech Lake, Red Lake and White Earth tribes.

Working with tribes

The Minnesota Department of Natural Resources is working with the tribes and has added the area surrounding the unnamed cervid farm as another to be monitored during the deer hunting season, according to Dave Olfelt, director of the division of fish and wildlife.

He told the committee that the department is estimating it will need $2.8 million for its CWD surveillance work this year, or $1,152,901 more than in 2020. Managing the area in Beltrami County adds an estimated $175,890 in surveillance and monitoring costs, according to the division director.

He told the committee that the DNR will require mandatory testing of deer harvested on the opening weekend in the managed zones where the disease has been detected in wild deer in recent years.

Sleeping giant: CWD threat to commodities

The importance of testing is only going to grow as we go forward. Committee member Rep. Josh Heintzeman, R-Nisswa, asked Larsen if researchers are monitoring for the prions shed by infected deer in the landscape and for the potential that they will be found on farm products, such as the sweet corn sold on the corner.

The country of Norway banned the importation of hay and straw from CWD positive regions several years ago.

"I believe this is a sleeping giant with respect to commodities," said Larsen. "I grew up on a farm, raised corn and soybeans and I want to make sure we do great science looking at that issue," he told the committee.

"We have and are performing tests looking at oats, alfalfa, and barley where we can experimentally raise those plants exposed to prions in (the) laboratory," said Larsen.

Researchers in Wisconsin have been examining the risk of transmission of prions in commodities, and will be publishing their results soon, he said. He is interested in looking at the alfalfa industry in the southeastern part of Minnesota where wild deer have tested positive for CWD.

The research that led to the field test was made possible in part by $2 million awarded to the University by the legislature thanks to Legislative-Citizen Commission on Minnesota Resources funding. Representative Jamie Becker-Finn, DFL, Roseville, a committee member, emphasized what a big deal the spread of CWD is to the cabin and tribal deer country of the northern part of the state. The DFL legislator expressed her frustration that for two years now, LCCMR bills have not been moved in the Senate.

It's incredibly important to free these LCCMR dollars and support the University research, she said.

Larsen acknowledged the importance of the funding that has been received. He said the research team is continuing to work on four different tests, some of which are intended to make it possible to monitor CWD in the landscape. The team is also working with tribal partners as well as other universities as part of a national network of teams looking at the threat posed by CWD.