Chronic Wasting Disease (CWD) - White-tailed Deer

CWD is a disease that can affect wild and captive cervids (deer, elk, moose, and caribou) in Iowa and is transmitted by a misfolded prion protein shed in saliva, nasal secretions, and other excreta. Prions are normal host proteins found throughout the body, however exposure to the infectious form can force a conformational shift that causes prions to aggregate in the brain. Prion diseases are uniformly fatal and pose a grave risk to long-term herd health in populations afflicted by this disease.

CWD can be transferred from deer to deer via direct contact and contact with bodily fluids. Therefore, prevalence and spread increase with deer density. However, abnormal prion proteins that are shed from CWD positive deer can persist in the environment for many years, which can additionally infect deer. As a result, disease prevalence is also independent of deer density. There is currently no viable vaccine or other treatment. Consequently, once a wild deer herd has become infected, removal is nearly impossible and increased prevalence is extremely likely. Deer management strategies generally have focused on mitigating the prevalence and spread of the disease via population reduction or some form of isolating or quarantining infected areas. Recent research in Wyoming has found that CWD has been documented to have strong population-level effects.

What Hunters Need to Know:

First detected in Allamakee County in 2013, CWD has been slowly increasing its footprint to include 10 counties and 133 positive wild deer. The Iowa DNR has been monitoring for CWD since 2002, then increased its effort in the immediate area surrounding the positive deer to help determine the presence and prevalence of the disease. 

Though CWD testing is not regulated as a food safety test in the United States, it is our best way to keep these misfolded prions out of the human food chain; however, the Centers for Disease Control and Prevention recommend, when hunting in areas with CWD, strongly consider having the deer tested for CWD before you eat the meat. If your animal tests positive for CWD, do not eat that animal. For further recommendations, refer to information provided by the Centers for Disease Control and Prevention.

The Iowa DNR has created a number of special deer management zones that offer opportunities for hunters who are willing to harvest deer in specific areas.

This option is available to hunters both in- and out-of-state for cervids harvested in Iowa that either:

    • Do not meet the DNR’s surveillance criteria (i.e. fawns)
    • Are harvested in counties or management zones that have already exceeded surveillance quotas
  • Carcass Transport

Under Iowa law, hunters cannot transport into the state the whole carcass of any cervid (i.e., deer, elk, moose) taken from a CWD-infected area. Only the boned-out meat, the cape, and antlers attached to a clean skull plate (from which all brain tissue has been removed) are legal to transport into Iowa. 


How to Help Stop the Spread:

  • Become a CWD Ambassador

Chronic Wasting Disease Ambassadors is a collaborative education program between the Iowa DNR and Iowa State University Extension and Outreach that seeks to help Iowans address the challenge of Chronic Wasting Disease. The goal of the program is to develop a small, connected, and well-educated network of local leaders to effectively communicate about the management and mitigation of CWD.

  • Carcass disposal

Hunters who harvest deer in counties where chronic wasting disease has been confirmed can avoid unintentionally spreading disease to new areas by not moving carcasses out of those counties, and disposing of them at landfills when possible or burying them on the land where they were taken. 

  • Baiting

Chronic wasting disease spreads from deer to deer through a misshapen protein in the saliva, feces, urine and blood from an infected deer that can last in the environment for years, spreading the disease long after the source deer is dead. To help prevent the spread, hunters are encouraged to not set out mineral licks or bait that will congregate deer, thus potentially increasing disease transmission. 

mineral licks and baiting are disease spreading sites

As a temporary measure, hunters can cover old mineral licks with pallets and surround them with fences to exclude deer. Permanent mitigation requires excavation and soil replacement. 

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Chronic Wasting Disease Public Meeting, 12/03/20, Iowa DNR