Chronic Wasting Disease

General CWD Information

Since Chronic Wasting Disease (CWD) was first identified in wild deer, it has been detected in 25 states, 2 Canadian provinces, South Korea, Norway, and Finland. To date CWD has not been detected in California. This is a disease of major concern for cervids and may negatively impact these prey populations where it occurs. Through legislation and geography, California is at relatively low risk for CWD; however, it has the potential to spread to California’s deer and elk populations, and surveillance for the disease will remain a priority for CDFW. See the Q&A below to find out more about this devastating disease and what you can do to help.

What is chronic wasting disease?

CWD is a fatal neurologic disease of cervids (e.g. deer, elk, moose, reindeer). It is caused by a misfolded form of a normal protein, known as a prion. The misfolded proteins aggregate in nervous tissues causing progressive damage to the brain of infected animals. CWD belongs to a group of human and animal diseases called transmissible spongiform encephalopathies (TSE). Examples of TSEs in animals include bovine spongiform encephalopathy (BSE) in cattle, also known as “mad cow disease,” and scrapie in sheep and goats, which has been known to veterinary medicine for over 200 years. Creutzfeldt-Jakob disease (CJD), a sporadic prion disease arising in 1:1,000,000 people, and variant Creutzfeldt-Jakob disease (vCJD), which has been linked to the consumption of infected cattle during the “mad cow disease” outbreak in Great Britain and Europe in the 1990s, are examples of TSEs in humans.

How is chronic wasting disease spread?

The misfolded prion that causes CWD is infectious to other cervids and can be spread through direct contact with infected individuals or through an environment contaminated with infectious material. Infectious prion has been detected in the urine, feces, and saliva of infected animals. Carcasses and tissues of infected animals also contain infectious prions and may spread the disease if left out on the landscape. The prions are very stable and difficult to disinfect once in the environment.

Where is chronic wasting disease?

Chronic wasting disease (CWD) was first described in mule deer at a captive facility in Colorado in 1967. Since then, CWD has been diagnosed in deer, elk, and moose populations in 26 states and four Canadian provinces. It has also been found in captive elk and Sika deer in South Korea and most recently in free-ranging moose and reindeer in Norway. For a link opens in new windowmap of current known CWD infected populations in North America, please visit the United States Geological Survey (USGS) CWD page. A timeline of the spread of CWD can be found by visiting the link opens in new windowChronic Wasting Disease Alliance website.

What are the symptoms of chronic wasting disease?

The progression of chronic wasting disease (CWD) in an infected animal is very slow. It may take months or even years for clinical signs to appear. Infected animals gradually lose body condition, becoming emaciated or “wasted.” They may also show abnormal behaviors such as a wide stance, staggering gait, or inability to keep their head up.

What should I do if I see a sick deer or elk and am concerned it might be chronic wasting disease?

To date, chronic wasting disease has not been detected in California, and it is important to note that many other conditions that affect deer in California can produce these clinical signs. However, the Department’s Wildlife Investigations Laboratory investigates sick or dead wildlife and is particularly interested in deer and elk that display clinical signs consistent with CWD: emaciated or “wasted,” abnormal behavior, staggering gait, head and ears lowered. Testing these animals for CWD is an integral part of ongoing CWD surveillance efforts in California, and we often rely on members of the public to report sick and dead animals. We ask that any deer exhibiting abnormal signs be reported via our online mortality reporting form or by contacting the CDFW Wildlife Investigations Laboratory directly at (916) 358-2790.

What is California doing?

Currently, neither California nor any neighboring states has had a case of CWD. Legislation and regulatory actions taken by California since the 1990's help keep the risk of importing the disease to a minimum. These include limiting and regulating the importation of captive deer and elk (and other cervids) into California (link opens in new tab or windowCCR Title 14, Section 671), limiting what hunters can bring in from out-of-state hunts (no skull, no backbone) (link opens in new tab or windowCCR Title 14, Section 712), and banning the feeding of wildlife to prevent artificially congregating susceptible animals (link opens in new tab or windowCCR Title 14, Section 251.3).

Since 1999, California has tested 4500 deer and elk for CWD. The majority of these samples were obtained from hunter-harvested animals. To date, no CWD has been found. In 2017 the California Department of Fish and Wildlife developed an interagency CWD Task Force responsible for crafting a surveillance and management plan for the state. In that same year CDFW also restarted its active surveillance program, collecting samples from a variety of sources including; hunter harvested animals, animals hit by car, and animals brought in to the Wildlife Investigations Laboratory for disease investigation. CWD prion has not been detected in any animal tested to date. Planning how to maintain and augment surveillance efforts is the current priority of the CWD Task Force.

Can chronic wasting disease be spread to humans?

There have been no documented cases of a human infected with CWD. However, CDFW and the Centers for Disease Control and Prevention (CDC) recommend that hunters do not eat meat from deer that test positive for CWD or otherwise appear sick. In addition, CDFW recommends that hunters wear latex or nitrile gloves when field-dressing and processing animals, and that hunters wash their hands and disinfect tools after processing.

What if I am hunting out-of-state?

To prevent the accidental importation of CWD infected tissues into the state, the California Code of Regulations, Title 14, link opens in new windowSection 712. Prohibits hunters from importing or possessing carcasses with a skull or backbone still attached. If you are hunting out of state, please do some research and review the regulations related to CWD for that state, a link opens in new windowtable(PDF) listing the regulations for all 50 US states can be found through the Michigan Department of Natural Resources. Also, if hunting in a CWD positive state, make sure to check with that state’s wildlife agency for information about hunter check stations, possible mandatory testing, and getting your meat tested in the state it is harvested. If meat from an animal brought into California ends up testing positive, we ask that you contact the CDFW Wildlife Investigations Laboratory at (916) 358-2790 to let us know. CDFW may incinerate meat from a CWD infected animal upon request.

How is chronic wasting disease diagnosed?

The only approved tests in free-ranging animals are post-mortem tests. These include directly testing lymph node and brainstem for the presence of the prion associated with CWD. For this reason, sampling hunter-harvested animals remains the most reliable method for obtaining sufficient numbers to test.

Surveillance is key to keeping California deer and elk CWD free. See the Interactive map below for information about past surveillance results and future testing locations. Check back around the start of the 2019 deer season for the new CWD surveillance locations / hunter check stations. At these locations hunters can get their deer tag validated while contributing to the important cause of CWD surveillance.

For information about individual surveillance locations such as dates, times, address, please click on the deer icons on the map. A link opens in new windowfull table of dates, and sampling locations (PDF) is also available. Please consider stopping by one of our sampling locations next hunt season to get your deer tested for Chronic Wasting Disease.

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