A preliminary screening test strongly indicates that a deer harvested by a hunter last November near Pine Island in southeast Minnesota had Chronic Wasting Disease (CWD), according to the Minnesota Department of Natural Resources (DNR). CWD is fatal to deer, elk and moose but not known to affect human health.
If the National Veterinary Services Laboratory in Ames, Iowa, confirms the University of Minnesota’s preliminary diagnosis, it marks the first time CWD has been found in Minnesota’s wild deer herd. An official confirmation is expected by next week.
“This is very unfortunate,” said Tom Landwehr, DNR commissioner. “Minnesotans have done much to prevent CWD from entering our wild deer population. The good news is that we are well prepared for an attempt to control the disease and to possibly eliminate it.”
The DNR is already implementing the state’s CWD response plan. In the weeks ahead, the DNR will take steps to learn more about how prevalent the disease is in the area and will take actions based on that information.
In states where CWD has become well established, efforts to eliminate it from wild deer populations have been unsuccessful. The disease, if unmanaged, can spread and occur at high enough rates to impact long-term deer populations.
“We found this case of CWD early because we were actively looking for it,” said Landwehr. “Since 2002, we’ve tested more than 32,000 hunter-harvested deer, elk and moose as part of an early detection strategy. We’ve long believed the best way to manage this disease is to find it early and then react quickly.”
The deer presumed to have CWD was taken by a hunter this past fall about three miles southwest of Pine Island in Olmsted County. The hunter allowed the DNR to take a lymph node sample from the deer when he registered it. Recent microscopic analysis of that sample strongly indicates that the animal had CWD. The hunter has been informed of the results. It is not known how the deer contracted the disease.
Lou Cornicelli, DNR big game coordinator, will lead the agency’s CWD response team. He said the critical first step is to conduct an aerial survey to determine the number and distribution of deer in the Pine Island area. Because this area of the state is almost entirely in private ownership, the second step will be to talk with landowners in the area to seek their cooperation in collecting additional samples and to identify where additional samples can be collected.
Sample collection could take the form of a late winter deer hunt, landowner shooting permits, or sharpshooting in conjunction with cooperating landowners who provide permission. The purpose of the sampling is to collect needed additional CWD samples to assess disease distribution, and also to reduce the potential for the disease to spread.
Michelle Carstensen, the DNR’s wildlife health program leader, said the prevalence of CWD is likely low. “We sampled 524 deer this past hunting season in the Pine Island area and found only one that appears to have CWD,” said Carstensen. She added that the DNR did not find CWD in a total of 2,685 samples taken throughout southeastern Minnesota in 2009 or 500 samples taken in 2008 along the Wisconsin border, from Houston County northward to St. Croix State Park in Pine County.
The DNR has been on the lookout for CWD since 2002, when it was first detected at a domestic elk farm in central Minnesota. In recent years it has put additional focus on southeastern Minnesota. That’s because the disease was detected in 2008 at a domestic elk farm near Pine Island, and because southeastern Minnesota abuts Wisconsin which has had CWD for many years. The domestic elk herd at Pine Island was eliminated after a seven-year-old female was found to have CWD. Three other elk were found to have CWD during the removal effort.
Though it is not known exactly how CWD is transmitted, it is thought to be primarily from animal-to-animal by infectious agents in feces, urine or saliva. CWD can also persist in the environment and may be contracted from contaminated soil. The movement of live animals is one of the greatest risk factors in spreading the disease to new areas.
CWD is a fatal, animal brain disease. The National Center for Disease Control (CDC) and World Health Organization have found no scientific evidence that the disease presents a health risk to humans. Still, the CDC advises against eating animals known to have CWD. The disease is found in 13 other states and two Canadian provinces, including Wisconsin, North Dakota and South Dakota.