Last week, the Iowa Department of Natural Resources (DNR) confirmed its first case of Chronic Wasting Disease (CWD) in wild deer. The announcement was not a complete surprise—Iowa’s six neighboring states are all currently struggling with the contagious disease in wild populations.
CWD primarily affects the brains of elk and deer, causing abnormal behavior, extreme weight loss, and ultimately death. Since its discovery in the 1960s, the disease has been detected in 21 U.S. states and two Canadian provinces. There is no scientific evidence suggesting that humans can contract the disease. However, health concerns and perceptions can dissuade hunters from harvesting deer in infected regions, hurting economies and leaving diseased herds unchecked. Surveillance and management programs for the disease are also expensive and can draw resources away from other wildlife management efforts.
The infected wild deer was originally harvested in Northeast Iowa early last December near a region of Wisconsin containing high rates of the disease. Iowa has been expecting and preparing for detection in wild deer since the disease was first detected in the state in 2002. “We have been testing for CWD in Iowa’s deer herd for more than a decade and are optimistic, given the extensive data we have collected, that we have caught this early,” said DNR director Chuck Gipp in a press release.
Tackling the Disease
Early detection of CWD is essential since it can be extremely difficult to eradicate once it establishes itself in a region. The state’s surveillance strategy has included sample collections from harvested wild and captive deer throughout the state, but the DNR invests extra effort in counties neighboring infected regions of Wisconsin and Illinois. Since 2002, the state has taken more than 650 samples from within a five-mile radius of where the infected deer was harvested this winter.
The Iowa DNR is beginning to implement a disease response plan. “The next step will be to focus our monitoring efforts in the area where the animal was harvested and work closely with local landowners and hunters to gather more information.” Gipp said. Increasing sampling from this region will help determine whether this is an isolated case of the disease or if the problem is more widespread.
CWD is not completely new to Iowa. The state has been managing the disease in captive populations at breeding and hunting preserves since 2012. In fact, biologists have found a total of 13 cases of the disease distributed between three facilities. Captive facilities can be quickly quarantined, but disease management in wild populations presents new challenges. “They’re wild animals, so you don’t have a lot of control over them or what kind of contact they have,” said Iowa DNR spokesperson Kevin Baskins. Unfortunately scientists believe the disease can be spread by both direct and indirect contact between deer. As a result, the Iowa DNR plans to provide hunters and landowners with tips on minimizing both types of contact. Other states, for example, have already demonstrated that avoiding use of salt licks and deer feed on personal property or for baiting animals during hunting season may help limit direct contact between deer and the spread of the disease.
Minimizing indirect contact presents a bigger challenge. An abnormal protein called a “prion” causes CWD. These infectious proteins can survive a long time in the carcasses of infected animals or even in soil. Baskins notes the Iowa DNR will remind hunters about how to properly dispose of animals and other materials to minimize indirect contact and disease spread. In addition, the National Institutes of Health and the Centers for Disease Control and Prevention recommend wearing protective gloves when handling carcasses and, to remain safe, not consuming the brain, eyeballs, or spinal cord of harvested deer.
Neighboring states have been dealing with the disease in wild populations for longer, and may provide a good model for disease management. “I think one of the advantages that Iowa has is that we had CWD in all bordering states,” Baskins said. “We have the opportunity to kind of look at other states for what worked there and what didn’t work.” He says this is one of the things that the state will consider as it continues to formulate its response plan.
This article was originally published at The Wildlife Society, April 18, 2014.