Chronic Wasting Disease: What You Should Know

Conservation Featured

Chronic wasting disease poses serious threats to North America’s deer and elk populations, and the hunting industry, too. Here’s what you should know about this always-fatal disease.

What is CWD?

CWD is a contagious neurological disease that slowly kills every captive or free-ranging deer, elk, moose or caribou it infects. The disease is caused by misfolded, infectious proteins called prions. According to the Chronic Wasting Disease Alliance, prions can be found in the tissues and body fluids of infected deer, but they’re most prevalent in the animals’ eyes, brain, tonsils, spleen, lymph nodes and spinal cord. Prion-related diseases are fatal and cannot be treated.

In a Joe Rogan Experience podcast in August, the longtime CWD project leader for the U.S. Geological Survey’s National Wildlife Health Center said the disease causes holes in the brain, resulting in progressive neurological degeneration that ends in death. Bryan Richards also said CWD incubates and progresses in deer and other cervids for two years before the animal shows clinical signs of disease. Those signs include weight loss, excessive salivation and loss of awareness and fear of humans. However, deer likely start spreading the disease soon after contracting it.

How Does CWD Spread?

Knowing how the disease is spread is the first step to solving the problem. Photo credit: Wisconsin DNR

According to the Centers for Disease Control and Prevention, CWD prions likely spread between animals through feces, saliva, blood and urine, either through direct contact or indirectly through contaminated soil, food or water. Researchers also think CWD persists in the environment a long time.

It’s also possible that hunters inadvertently spread CWD by transporting infected deer parts home from distant hunts and discarding them outdoors. A Quality Deer Management Association article found hunters from 49 states killed deer in four CWD-infected Wisconsin counties during the 2016-2017 season. The article said many of those hunters likely returned home with CWD-infected carcasses, given that region’s high infection rates. Carcasses discarded outdoors shed prions into the environment, where they remain infective long after the body decomposes.

Where is CWD Found?

CWD has steadily spread since its discovery in mule deer at a Colorado research facility in the late 1960s. Richards said the once-isolated disease has now been identified in 25 states, three Canadian provinces, and Norway, Finland and South Korea. The disease is likely present but undetected in other places, but testing is up to individual states, and funding for tests is often lacking. Further, testing live animals for the disease is expensive and difficult.

Why You Should Care

Deer often don’t show signs of CWD until their final few weeks. Photo Credit: John Hafner

  1. CWD is a threat to deer, deer hunting and the hunting industry itself.

Because CWD is always fatal, it poses a serious threat to deer populations. Therefore, it also threatens the bowhunting industry, which relies heavily on white-tailed deer for business, sustenance and recreational value.

Most bowhunters pursue deer for its lean meat, trophy potential and the fun of being outdoors with friends and family. By bowhunting deer, millions of people help fund outdoor recreation’s future. After all, most state fish and wildlife agencies rely on two funding sources– hunting and fishing license fees; and federal excise taxes paid on firearms, ammunition, fishing tackle and archery gear – to pay for wildlife conservation and management programs. Without deer, the industry and the nation’s conservation efforts would suffer. To comprehend the deer’s importance to those funds, consider how recreational fishing would suffer without walleyes or largemouth bass.

  1. Could CWD become a Human-Health Issue?

Because prions are not alive, they can’t be “killed” by cooking meat at high temperatures. Therefore, thousands of people in Wisconsin alone have likely eaten venison from CWD-infected deer. Although there’s no evidence the disease can affect humans, researchers can’t rule out the possibility. Health officials urge hunters to get their deer tested if they hunt areas where CWD is present, and advise not eating the meat if the deer tests positive for CWD.

Know the Regulations

Wildlife agencies in states without CWD focus on prevention. Many have imposed hunting regulations that forbid feeding or baiting deer, and others prohibit using urine-based scent products. Most agencies ban people from moving live animals or carcasses into their state.

Bowhunters should read state game laws and area-specific regulations before hunting. You can find your state’s hunting regulations on the agency’s website or at local or regional offices. Where scents are allowed, choose certified deer-attractant lures that reduce CWD risks. Read more here. It’s your responsibility to know and follow game laws, and do all you can to control the disease.

Get Your Deer Tested

If you have any suspicion CWD is in your area, have your deer tested. Photo Credit: MLive

Industry leaders are urging more research and surveillance on deer nationwide. They want to help wildlife agencies better understand CWD, and possibly control or manage it. Hunters can help by testing their deer for the disease.

Those tests also help you decide whether to eat meat from deer shot in CWD-infected areas, even though they’re not considered food-safety tests. The test merely reveals whether it detected CWD. It does not certify deer as CWD-free. Hunters must decide whether to consume the venison.

Contact your state wildlife agency or a conservation warden for appropriate CWD testing procedures and where to submit samples.

Know Your Risk

Even though there’s no evidence CWD can infect humans, health officials recommend hunters wear latex or rubber gloves when handling venison. Hunters should also avoid cutting through the spinal cord except to remove the head. Proceed carefully to avoid contaminating nearby meat.

To learn more about CWD, and read frequently asked questions, visit

Find a store near you.