Chronic Wasting Disease Background

Chronic wasting disease (CWD) is a fatal nervous system disease known to naturally infect white-tailed deer, mule deer, moose and elk. It belongs to the family of diseases known as transmissible spongiform encephalopathies (TSE) or prion diseases. Though it shares features with other prion diseases, like mad cow disease in cattle and scrapie in sheep, it is a distinct disease known to only affect members of the deer family. CWD has been discovered in wild deer or elk herds in 11 states and two Canadian provinces.

Wisconsin Efforts

The discovery of CWD in southern Wisconsin represents a significant threat to the state's white-tailed deer population and the culture of deer hunting in the state. Wisconsin has more than 700,000 deer hunters who have harvested an average of 460,000 deer annually during the past decade. Deer hunting contributes more than 7 million days of recreation each year. Deer hunting annually generates more than $500 million dollars in retail sales and nearly $1 billion in total impact to the state’s economy.

An extensive CWD surveillance program has been conducted in Wisconsin since 2002. Sample intensity has been sufficient in the majority of the state to have a high degree of confidence that CWD would have been detected if it exists at 1% prevalence. For details on the numbers tested and positive deer please view the test results page.

Analysis of the sex and age composition of positive deer has shown that very few fawns are infected; only 20 out of more than 12,500 tested. Disease prevalence increases with age and the rate of increase is faster in males than in females. Only 2-3% of yearling females and males from the core area in southern Wisconsin have tested positive for CWD. This increased to 4-5% of females and 10% of males for deer 2 years old or older.

There are consequences to not attempting to control the disease or an inadequate response: the prevalence and geographic distribution of CWD will increase and there will be long-term impacts on the deer hunting culture of Wisconsin and related industries and businesses. The results of ongoing research studies are needed to better understand the dynamics of the disease, its pattern of increase and spread, the role of environmental transmission, and the effect of management actions on the disease.

Public Dialogue

In the summer of 2007, the Department embarked on a public involvement effort to include the public in helping establish the next phase of CWD management in Wisconsin. The dialogue engaged the multiple and diverse interests potentially affected by the department’s disease and deer herd management decisions.

The goal of the CWD dialogue was for the public and the DNR to reach decisions on how to manage chronic wasting disease to minimize the impact of the disease on Wisconsin’s free-ranging deer population, the habitats and biological systems that include deer, the economy, hunters, landowners and others that benefit from a healthy deer herd.

Contact Information

For answers to questions relating to CWD in Wisconsin,
call the DNR operated toll free CWD information line 1-877-WISC CWD or email Wildlife Health.

Questions for Wildlife Management