Sunday, June 24, 2018


Minnesota's new CWD strategy
Larger view
A technician at the University of Minnesota's diagnostic laboratory prepares a deer lymph node for CWD testing. The lab is handling 13-thousand tests this year. So far none have turned up positive. (MPR Photo/Erin Galbally)
Three years ago hunters and wildlife specials were panicked by the possibility that Chronic Wasting Disease could enter the Minnesota deer herd. For most people that fear has faded. But efforts to stop the spread of the disease are still underway. In fact by the end of this week, University of Minnesota researchers will have completed tests on roughly 13,000 samples gathered from the fall deer hunt. Now after three years and no positive cases, the Department of Natural Resources plans to discontinue its wide scale surveillance program in favor of more targeted testing.

St. Paul, Minn. — It's a busy time at the University of Minnesota's Diagnostic laboratory. This is where thousands of deer lymph nodes, each in their own carefully labeled zip lock bag, come for testing. Michele Confeld wears a white lab coat and holds a vial filled with lymph node and liquid. Her lab processes about 400 tests for chronic wasting disease each day.

"Depending on how fast we can cut that's about how much we're running," she explains. "So one sample from cut to finish is about a day because we don't detect until the next day."

Each test costs about $20. Multiply that by 13,000 and it's easy to see how much this process costs. But according to the Department of Natural Resources that's nothing compared to $465-million deer hunters contribute to the state economy each year. That's made every penny spent chasing down the disease seem like a wise investment. Lou Cornicelli has been coordinating the DNR's Chronic Wasting Disease efforts. He says the information gleaned over the past three years is valuable. But he says it's now time to shift away from what he likens to searching for a needle in a haystack.

"If CWD shows up on the river out of Wisconsin we're going to test the southeastern part of the state," says Cornicelli. "We're not going to wait until it shows up across the river (in Minnesota) but are we going to go into Kittson County and just test the deer to look again probably not but we are going to keep up on what other states are doing with deer and that are exhibiting symptoms and also what's going on with domestic animals."

Aspects of chronic wasting disease continue to baffle scientists. It's a fatal neurological disease that affects members of the deer family. An infected brain develops a maze of tiny holes. It's not entirely clear how the disease is transmitted, but it may pass through body fluids like saliva. CWD is in the same family of diseases as BSE commonly known as "Mad Cow Disease." But unlike BSE, there's no proof that CWD can infect humans. Even so it can have a significant impact on hunter turnout. In Wisconsin hunter numbers have yet to rebound three years after the disease first surfaced near Madison.

The DNR's Lou Cornicelli says even though there have been no positive cases so far in Minnesota's wild deer population it doesn't rule out future possibility.

"We have a couple of things that are risky for us. One is simple basic deer biology that they move," explains Cornicelli. "You know young deer move away from their mothers and establish new home bases. We're not that far from the Wisconsin endemic area. Probably 70 air miles. In theory we could have deer crossing back and forth, which we do. Whether an infected deer crosses and infects Minnesota deer we don't know but that's a risk."

Cornicelli says another risk factor is the number of domestic elk in the state. So far two Minnesota elk have tested positive for the disease and all domestic elk carcasses are required to undergo testing.

Cornicelli says the DNR will continue to test wild deer but more on a case-by-case basis. During the next fall hunt for the first time in three years hunters will not be asked to donate their animal heads for testing. It also means, that the University of Minnesota's Diagnostic Laboratory will have at least a temporary reprieve from round the clock chronic wasting disease testing -- that is unless the disease is found near by.