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.
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.
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 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 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.
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.
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 (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).
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.
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.
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.
- Testing remains below our current surveillance goals. These goals are based on the number of individuals necessary to confidently confirm the absence of CWD in California.
- If we don’t test for CWD in California we can’t definitively say it isn’t here.
- Hunter harvest samples provide best mechanism for testing. In states where CWD is active, adult males are the most likely carrier of CWD in non-clinical animals due to their behavior.
- Detecting CWD early allows for the most response and management options.
- Check the “Surveillance Locations and Map” tab, which is updated before and during the hunt season.
- Call your local CDFW office to see about other options for getting your harvest sampled and tested.
- Ask if your local meat processor or taxidermist is participating in the surveillance program to help sample for CWD.
- Results will be posted at end of season.
- Check the "Find Your CWD Testing Results" tab at end of season, use the document number on your deer tag to find your results.
- Due to logistics of sampling and testing, expect results back in 2-3 months after testing.
- Because CWD has not been detected in California to date, waiting for results prior to consuming their meat is based on the hunter’s own comfort level. However, this may change if CWD is ever detected within California.
- Baiting and the feeding of wildlife in general was made illegal in California by CCR Title 14, Section 251.3. Baiting promotes the congregation of wildlife. When animals exist in close proximity they have increased opportunity to spread pathogens among themselves, which can result in outbreaks of a host of diseases from cholera in waterfowl, to mycoplasmosis in turkeys, to hemorrhagic disease in deer and elk.
- Should CWD ever reach California, baiting and the feeding of cervids in general would allow for increased contact between infected and susceptible individuals, and the rapid spread of this disease.
- The way these biologically based scent lures are produced allows for the possibility of CWD prions to be included in the scent lure. It is one way CWD could be moved into a new area; however, the likelihood or that happening or the level of risk that represents is unknown.
- The CWD prion can be excreted in urine and where CWD is present in captive cervids, prevalence tends to be high.
- Best practices and a precautionary approach recommend not using any urine or other biologically based scent lures for hunting in California as a means 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.