Prevention is the best approach
DNR conducts CWD surveillance to keep Minnesota deer healthy. The prevalence and geographic spread of CWD is increasing. Taking steps to better protect deer from disease is vital to Minnesota's hunting tradition and economy.
Proactive surveillance and precautionary testing for the disease is a proven strategy that allows DNR to manage CWD by finding it early and reacting quickly and aggressively to control it. These actions, which were taken in 2010 to successfully combat a CWD infection in wild deer near Pine Island, provide the best opportunity to eliminate the disease's spread.
An additional protection prevents whole carcasses of deer, elk, moose and caribou from anywhere in North America to be brought in to Minnesota. Until August 2016, whole carcasses could be brought in if they were not harvested in an area infected with CWD.
Recent focused surveillance efforts
2016: Due to the expansion of CWD in Iowa and Wisconsin, surveillance targeted nearly all of southeastern Minnesota during its firearms deer seasons. Intially, two male deer harvested 1 mile apart near Preston tested positive for CWD. These were the first wild deer found to have CWD since a deer harvested in fall 2010 near Pine Island tested positive. Additional testing resulted in nine more deer testing positive, bringing the total to 11 and prompting additional and expanded testing in 2017.
2014: Triggered by the detection of several CWD-infected deer in 2014 from Iowa's Allamakee County, the Minnesota DNR collected 411 samples in southeastern Minnesota deer permit areas 348 and 349. All test results were negative.
2012-2014: In mid-2012, a captive European red deer (Cervus elaphus) was found infected with CWD in a herd of approximately 400 animals from North Oaks. In response, DNR collected samples from 350 deer, all within a 10-mile radius of the farm on the northeastern edge of the Minneapolis-St. Paul metropolitan area. All test results were negative.
What is CWD?
CWD is a contagious neurological disease affecting deer, elk and moose. It causes a characteristic spongy degeneration of the brains of infected animals resulting in emaciation, abnormal behavior, loss of bodily functions and death.
CWD belongs to a group of diseases known as transmissible spongiform encephalopathies (TSEs). Within this family of diseases, there are several other variants that affect domestic animals:
- Scrapie, which has been identified in domestic sheep and goats for more than 200 years;
- Bovine spongiform encephalopathy (BSE) in cattle (also known as "mad cow disease"); and
- Transmissible mink encephalopathy in farmed mink.