Chronic Wasting Disease Surveillance

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 build up 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), also known as “mad cow disease”; and scrapie in sheep and goats. Examples of TSEs in humans include 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. 

CWD spreads through direct contact with the infectious, misfolded proteins (i.e., prion), from infected individuals or contaminated environment. Infectious prions can be excreted in urine, feces, and saliva of infected animals before they show any signs of the disease. Prions persist in animal carcasses and tissues, especially in the brain, spinal cord, and lymph nodes. Infected carcasses can contaminate the environment and spread the disease if left out on the landscape, as prions can persist for ten or more years in soils and be taken up by plants. 

Chronic wasting disease (CWD) was first described in mule deer at a captive facility in Colorado in 1967. Since then, CWD continues to be detected in free-ranging and captive deer, elk, moose, and other cervid populations in an ever-expanding number of states (including California), Canadian provinces, and countries. 

California's CWD dashboard tracks current cases in the state. See the United States Geological Survey (USGS)map of current known CWD infected populations in North America and the CWD Alliance's timeline of the spread of CWD.

The progression of CWD in an infected animal is very slow. After infection, an animal may not show clinical signs of CWD for months or even years. 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. 

CWD has now been detected in California’s deer/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. 

The WHL investigates sick or dead wildlife and is particularly interested in deer and elk that are skinny or “wasted,” show abnormal behaviors, or have a staggering gait. While deer could have a different condition that produce similar clinical signs, testing these animals for CWD is an integral part of ongoing CWD surveillance efforts in California. CDFW relies on members of the public to report sick and dead animals.  

Limit the Spread: Legislation and regulations enacted since the 1990s reduce the risk of importing the disease. These include restrictions on the importation of captive deer and elk (and other cervids) into California (CCR Title 14, Section 671 (opens in new tab)), what hunters can bring in from out-of-state hunts (no skull, no backbone) (CCR Title 14, Section712 (link opens in new tab)), a ban on the feeding of wildlife to prevent artificially congregating susceptible animals (CCR Title 14, Section 251.3(opens in new tab)), and a ban on the use or possession of cervid-derived biological materials such as scent lures (CCR Title 14, Section 714 (opens in new tab)).
 

Surveillance: California has been testing deer and elk for CWD since 1999, with most samples coming from hunter-harvested animals and the rest from vehicle-strike and other sources of deer and elk mortalities. Maintaining robust disease testing is needed to understand disease spread dynamics to better inform management decisions. 

In 2024, CDFW first confirmed CWD in California. The Fish and Game Commission adopted regulations in response to these detections that defined a CWD management zone and authorized the CDFW director to designate mandatory testing or testing and handling rules for hunter harvested deer within those management zones (CCR Title 14, section 708.5 (opens in new tab)). 

Management: CDFW developed a statewide CWD Management Plan outlining surveillance, response, long-term management, and communication strategies. Management actions will be determined by the prevalence and geographic distribution of CWD as determined through CDFW’s CWD surveillance efforts. General management objectives are to use current scientific understanding and management tools to keep prevalence low where CWD occurs and decrease transmission and spread of the disease to naïve populations.  

There are no documented cases of CWD affecting humans. Laboratory and population-based studies suggest that people may not be susceptible to CWD. However, other animal prion diseases, like “mad cow” disease, have caused lethal disease in humans so the risk to people may not be zero. 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 best tests for CWD require lymph node or brainstem samples taken from a deer or elk after death. However, significant work is going towards optimizing more sensitive, rapid and live-animal tests and these tests may be used as they become available and accepted.  

Bring the deer, or head, to a CDFW-operated sampling station or office or to a participating meat processor or taxidermist. Alternatively, you can collect and submit samples yourself by following these instructions.

Contact the Wildlife Health Laboratory about other testing options for your harvested deer or elk at (916) 358-2790 or cwd@wildlife.ca.gov. 

Follow the “Find your CWD Testing results” link or the main CWD page and scroll down. Enter your document (hunting tag) number, GOID or CWD sample bag # to find your results. 

Where CWD is known to occur, hunters should consider the possibility of harvesting an infected deer or elk. CDFW recommends waiting for a negative test result before consuming harvested animals. Testing does take time, often 3 weeks or more. 

• Baits artificially congregate wildlife, can change their normal behaviors, and increase the likelihood of spreading diseases, including CWD.

Deer urine and other biologically-based lures are not to be possessed in California (CCR Title 14, Section 714 (opens in new tab)). Scent lures are produced using urine from captive deer. Captive deer are at greater risk for CWD, and scent lures may carry the infectious prions that cause CWD. These prions can remain in the environment for more than ten years and could be a source of infection for wild deer and elk. Therefore, the best practice is to avoid using any urine or other biologically-based scent lures for hunting in California to protect against inadvertently importing CWD prions. 

Field dress your harvest and leave everything you can at the site of harvest, especially the brain and spinal cord. If taking the head for sampling or taxidermy, ensure that the brain is either incinerated or disposed of appropriately at a landfill that accepts animal waste. Brain, spinal cord, and lymphatics contain the highest concentration of prions in animals infected with CWD and proper handling and disposal of those materials is an important safeguard to limit the spread of CWD. 

Know and follow the import and movement regulations for deer, elk, and moose harvests for California and every state through which you will travel. California’s  CCR Title 14, Section 712 defines harvested deer, elk and other cervid import restrictions and Section 2353 of the Fish & Game Code provides the declaration requirements. The Chronic Wasting Disease Alliance maintains a great up-to-date resource about the latest news regarding this disease and its spread, as well as records of current CWD-related hunting regulations.

We recommend that you have your harvests sampled and tested for CWD in the state where it was harvested. A best practice for importation is to bring back only packaged or boned-out meat and finished taxidermy mounts.

CCR Title 14, Section 712 regulations details what can legally be brought back into California. An easy way to remember the regulations is “no brain and no spinal cord,” and as a best practice CDFW recommends bringing back only packaged or boned-out meat and finished taxidermy mounts.

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:

1. Portions of meat with no part of the spinal column, brain or head attached (other bones, such as legs and shoulders, may be attached).
2. Hides and capes (no spinal column, brain tissue or head may be attached).
3. Clean skull plates (no brain tissue may be present, pursuant to Section 714 of these regulations) with antlers attached, if present. For the purpose of this section, the skull plate is defined as the paired bones (frontal, parietal, and temporal bones) that make up the top portion of the skull surrounding the brain and, in antlered animals, from which the paired antlers extend.
4. 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.
5. 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).
6. Upper canine teeth (buglers, whistlers, ivories).

• CDFW cannot test “meat” for CWD. While it is possible to test for and detect CWD prions in meat and other tissues, these tests are currently only available in specialized research labs and not for diagnostic or consumer use. 
• There is no “meat safety” test for CWD. For current testing options, results are reported as “Detected” or “Not Detected” for CWD and other prion diseases. That means we can be certain an animal is positive for CWD if the prions are “detected” but we cannot be certain the animal did not have CWD if the results are “not detected.” This is one of the major issues surrounding CWD and other prion diseases and is in large part because of the attributes of the pathogen itself (the prion) and the sensitivities of the currently available tests 
• Furthermore, if you brought back only the parts allowed by  CCR Title 14, Section 712 regulations, then the samples needed to perform an official CWD test are not available. These are the retropharyngeal lymph nodes or brainstem.
• Best practice is to have your animal tested for CWD in the state you are hunting, especially if that state or region has CWD. As such we recommend doing some research before hunting out-of-state to determine 1) CWD status of the state you are hunting in and 2) how to get an animal tested for CWD 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 themselves for testing for a fee.

Any harvested animal, or parts of, brought into California must be declared using CDFW’s Declaration/Importation of Fish and Wildlife entry form page. If the checkpoint is closed or unmanned when you return to California you are still required to submit your Declaration for Entry Form within 24 hours after entering the state.

The best practice is to bring your animal into compliance with CCR Title 14, Section 712 regulations in the state where you hunted. Some states will not let you leave a CWD-positive area without first removing the skull and backbone. Many states have passed similar rules to California’s making it unlawful to move the banned parts of harvested cervids from outside states into California or any of its neighbors. For more information on regulations in other states, see the CWD Alliance's CWD Hunting Regulations Map.

The CCR Title 14, Section 712 regulations still need to be followed. Only the following can be brought back:

2. Hides and capes (no spinal column, brain tissue or head may be attached).
3. Clean skull plates (no brain tissue may be present, pursuant to Section 714 of these regulations) with antlers attached, if present. For the purpose of this section, the skull plate is defined as the paired bones (frontal, parietal, and temporal bones) that make up the top portion of the skull surrounding the brain and, in antlered animals, from which the paired antlers extend.
4. Cntlers 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.
5. 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).
6. Upper canine teeth (buglers, whistlers, ivories).

If you would like to make a European mount, all residual brain matter and skull lining must be removed in compliance with CCR Title 14, Section 712 regulations.

We recommend contacting the Department and voluntarily relinquishing any meat or other parts. The Department will incinerate the potentially contaminated tissues. Hunters can decide how to deal with contaminated tissues—there is no requirement to relinquish the meat. Both the U.S. Centers for Disease Control (CDC) and the World Health Organization (WHO) recommend not consuming any tissues from CWD-infected animals. Additionally, improper disposal of meat or other parts from CWD-positive animals poses a risk to California’s deer and elk populations. Prions can survive in the environment for more than ten years, and can be absorbed by roots and distributed in growing forage.

If meat might be contaminated, do not bury it, throw it in the trash, leave it out for scavengers, or feed it to your dog. Incineration is the safest disposal method for contaminated meat or tissues.

If you have a positive test, your local CDFW office or the Wildlife Health Laboratory (phone: (916) 358-2790) will arrange for the meat or tissues to be picked up and/or destroyed at no cost to you. 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.