The number of deer confirmed positive for chronic wasting disease, or CWD, in Iowa has seen a steady rise over the past few years. However, southeastern Iowa remains relatively free from the disease, compared to other parts of the state.

CWD is an always-fatal neurological disorder that affects white-tailed deer and other cervids. It is caused by misfolded prions that damage the central nervous system. Deer infected by CWD appear to be unsteady, and show signs of neurological damage. The disease is tested in deer by sampling the lymph node under the jaw after death. Iowa has tested over 111,000 deer since 2002. The first positive case was found in Allamakee County in 2013. In 2025, that number has risen to 541 deer in 31 counties.

Within Iowa, the areas which have seen the highest prevalence of CWD include south central and northeastern Iowa. Southeastern Iowa, by comparison, is relatively CWD-free, but testing in recent years has revealed the first batch of positive cases in the area. 

State deer biologist Jace Elliott, with the Iowa Department of Natural Resources, says that despite a few cases being spotted nearby in Muscatine and Des Moines counties, Washington County has not yet had a positive test. Elliott says, “We don’t believe that there’s a high prevalence in these counties, we believe that we just began detecting some of the first cases as far as our surveillance data would suggest. So if there is chronic wasting disease currently in Washington County, we haven’t found it yet and it’s likely at a very low prevalence.”

The risk of humans contracting a prion disease, such as CWD, appears to be low, but caution is still advised for those who might work in close contact with deer.

CWD is transmitted from deer to deer by direct contact and contact with bodily fluids. Deer density plays a large role in the spread and prevalence of the disease.