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 tissues, particularly the brain, causing progressive damage. 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.
The misfolded prion that causes CWD is infectious to other cervids and can be spread through direct contact with infected individuals or through contact with a contaminated environment. Infectious prions can be excreted in urine, feces, and saliva of infected animals, even before they show any signs of the disease. Carcasses and tissues, especially brain, spinal cord, and lymph nodes, of infected animals contain infectious prions and may spread the disease if left out on the landscape. Prions are very stable and difficult to disinfect, persisting for years in a contaminated environment able to infect a susceptible deer or elk.
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, free-ranging moose and reindeer in Norway, and free-ranging moose in Finland. For a map 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 Chronic Wasting Disease Alliance website.
The progression of chronic wasting disease (CWD) in an infected animal is very slow. It takes months or even years following infection for clinical signs of CWD to appear. Infected animals gradually become skinnier, emaciated or “wasted” despite continuing to eat. They may show abnormal behaviors such as a wide stance, staggering gait, or inability to keep their head up.
To date, chronic wasting disease has never been detected in California’s deer or elk populations. If you see a sick or dead deer that could be due to CWD, please use our online mortality reporting form (preferred) or contact the CDFW Wildlife Health Laboratory directly at (916) 358-2790. It is important to note that many other conditions that affect deer in California can produce similar clinical signs. However, the Department’s Wildlife Health Laboratory investigates sick or dead wildlife and is particularly interested in deer and elk that display clinical signs consistent with CWD: skinny 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 rely on members of the public to report sick and dead animals.
Prevention: Legislation and regulations enacted since the 1990's help keep the risk of importing the disease to a minimum. These include severely limiting the importation of captive deer and elk (and other cervids) into California (CCR Title 14, Section 671)), limiting what hunters can bring in from out-of-state hunts (no skull, no backbone) (CCR Title 14, Section 712)), and banning the feeding of wildlife to prevent artificially congregating susceptible animals (CCR Title 14, Section 251.3).
Surveillance: Since 1999, California has tested over 5,500 deer and elk for CWD, the majority from hunter-harvested animals. To date, no CWD has been found. In 2017, CDFW developed and implemented a statewide CWD surveillance plan, renewing our active CWD surveillance program and increasing yearly CWD testing goals. CWD prion has not been detected in any animal tested to date.
Management: CDFW initiated an interagency CWD Task Force to develop and implement a CWD management plan. The surveillance portion of that has been implemented and the task force is working to finalize the management plan.
There are no documented cases of CWD affecting a human. However, the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) 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.
Currently, the only approved tests for CWD require lymph node or brainstem samples, taken after death, to detect the prion associated with CWD. However, this is an area of considerable research and we hope additional rapid and live-animal tests become available in the future.
- So we can detect it early when it does arrive and respond quickly.
- Detecting CWD early allows for the most response and management options.
- Samples from hunter-harvested animals are the most accessible, and often best, samples for CWD testing. In states where CWD is active, adult males are the most likely carrier of CWD in non-clinical animals due to their behavior.
- Check the “Surveillance Locations and Map” tab before you go hunting to look for a volunteer CWD sampling station near you. This is updated before and during the hunt season.
- Call your local CDFW office about other options for testing your harvested deer or elk.
- Ask if your local meat processor or taxidermist is participating in the CWD surveillance program. If they are participating consent to have your harvest sampled and tested.
- Check the "Find Your CWD Testing Results" tab at end of season, use the document number on your deer tag to find your results.
- Results will be posted 2-3 months after the end of the last deer or elk hunt season ends.
- CWD has never been detected in California’s deer or elk, therefore the risk of inadvertently consuming infected meat from an animal harvested in California is considered low to none. However, waiting for results prior to consuming meat is based on the hunter’s own comfort level.
- Baiting and the feeding wildlife is illegal in California ( CCR Title 14, Section 251.3).
- Baiting artificially congregate wildlife and increases the likelihood of spreading diseases, including CWD.
- These scent lures are produced using deer urine, which can contain infectious CWD prions. It is one way CWD could be imported into California.
- Best practices are to avoid using any urine or other biologically based scent lures for hunting in California to protect against inadvertently importing CWD prions.
- Check the CWD status of state you are planning to hunt in.
- Visit the web page or call the agency for the state you are planning to hunt in to find out about local distribution of CWD state where you plan to hunt, whether there are any requirement for CWD testing, or if there is a way to get your harvest voluntary tested.
- Review the regulations concerning CWD for the state you plan to hunt in. The Chronic Wasting Disease Alliance maintains a great up to date resource about the latest news regarding this disease and its spread.
- Always keep in mind California Code of Regulations Title 14, Section 712 regulations and the Section 2353 Fish & Game Code declarations requirements when bringing any harvested cervid parts back to California.
- Title 14 California Code Regulations § 712. Restriction of Importation of Hunter-Harvested Deer and Elk Carcasses.
- It is unlawful to import, or possess any hunter harvested deer or elk (cervid) carcass or parts of any cervid carcass imported into the State, except for the following body parts:
- (a) portions of meat with no part of the spinal column, brain or head attached (other bones, such as legs and shoulders, may be attached).
- (b) hides and capes (no spinal column, brain tissue or head may be attached).
- (c) clean skull plates (no brain tissue may be present) with antlers attached.
- (d) antlers with no meat or tissue attached, except legally harvested and possessed antlers in the velvet stage are allowed, if no meat, brain or other tissue is attached.
- (e) finished taxidermy mounts with no meat or tissue attached (antlers in the velvet stage are allowed if no meat, brain or other tissue is attached).
- (f) upper canine teeth (buglers, whistlers, ivories).
- Note: Authority cited: Sections 200, 203, 240 and 2355, Fish and Game Code. Reference: Sections 200, 203 and 2355, Fish and Game Code.
- Basically, “no skull, no backbone” to avoid importing the highest risk tissues for carrying prion.
- Best practice and best recommendation is to only bring back packaged meat and/or finished taxidermy mounts.
- If you brought back the parts allowed by California Code of Regulations Title 14, Section 712 regulations, then the samples needed to perform an official CWD test are not available, that is the retropharyngeal lymph nodes or brainstem.
- While any tissue can be tested for the prion that causes CWD, current testing options should not be used as a food safety test. A “Not Detected” result for meat does not guarantee prion was not present in the animal or its meat. This is one of the major issues surrounding CWD and other prion diseases, because of the type of pathogen and sensitivity of the currently available tests, the tests are not negative or positive they are “Detected” or “Not Detected” and a “Not Detected” is not necessarily the same as negative.
- We recommend any hunter harvesting an animal in a region that CWD has been detected get their animal tested in that state. As such we recommend doing some research before hunting out-of-state to 1) confirm CWD status of the state you are hunting in and 2) if a CWD-positive state confirm how they can get their animal tested in the state it was harvested.
- Some labs such as Colorado State University Diagnostic Veterinary Laboratory or the Texas A&M Veterinary Medical Diagnostic Laboratory allow hunting public to submit samples for testing for a fee.
- Per Section 2353 Fish & Game Code any wildlife being brought into California must be declared using the Declaration for Entry Form (PDF).
- Best practice is to bring your animal into compliance with Title 14, Section 712 in the state you hunted. Removing the skull and backbone at the CA border may bring you into compliance with California law, but it risks introducing CWD to our neighboring states and may even be against the law of surrounding states.
- Nevada Senate Bill 85 passed in 2019 introduced similar rules to California Code of Regulations Title 14, Section 712 in Nevada making it unlawful to bring the skull or backbone of cervids harvested outside of Nevada into that state.
- If you are bringing parts from a harvested animals into California you should declare the your harvest at a border checkpoint to ensure compliance with California regulations including Title 14, Section 712. At this time you will be asked to submit a Declaration for Entry Form (PDF).
- If the checkpoint is closed or unmanned when you return to California you are still required to submit your Declaration for Entry Form to Department of Fish & Wildlife, 1416 9th Street, Law Enforcement Division, Sacramento CA 95814 within 24 hours after entering the state.
- Keep in mind other states along the way may also have regulations and checkpoints regarding the movement of wildlife across their state lines. Some states will not let you leave a CWD positive area without first removing the skull and backbone. A table(PDF) listing the regulations for all 50 US states can be found through the Michigan Department of Natural Resources.
- Best recommendation is to have the animal taxidermied in the state it was harvested.
- However, if you have a specific taxidermist you want to use in California, then the CCR Title 14, Section 712 regulations still need to be followed. Only a fully cleaned skull cap with no remaining brain or associated nuerological tissue may be legally brought into California.
- If you would like to make a European mount, keep in mind that without completing the full preparation it is inevitable that infectious material associated with residual brain matter and the lining of the skull will be returned to California with the skull. Simply boiling the skull or pressure washing the skull will not destroy the prion and will not remove all the tissue, and it will not be legal to bring back into California.
- Both the CDC and WHO recommend not consuming any tissues from CWD-infected animals.
- Improper disposal of contaminated meat in California is the highest risk to introducing CWD to California Deer herds. Please do no bury, throw in trash, leave out for scavengers, or even take contaminated meat to landfill.
- Prion can survive in the environment for 10+ years, and has even been shown to be absorbed by plants and distributed to growing foliage.
- Incineration is the safest disposal method for contaminated meat.
- CDFW will pick up and destroy contaminated meat at no cost to you.
- Call or email the CDFW Wildlife Investigations Laboratory at (916) 358-2790, and be prepared to provide the following information:
- State of harvest
- CWD test results
- Location of harvest
- Location of processing
- Weight of meat to be destroyed
- Contact information
- If your CWD positive animal was processed by a meat processor in California please be sure to inform your processor so that they can take the proper decontamination procedures.