Disease and Mortality Monitoring

Bighorn Sheep Capture

The WIL has a critical role in expanding the knowledge of wildlife infectious and non-infectious diseases, the effect of disease on wildlife populations, and health monitoring for the reintroduction of elk, bighorn sheep, and antelope to their native ranges in California.

WIL staff actively collaborate with other researchers. The results of disease investigations are published in scientific journals. This information is used by CDFW, agency partners, universities, and other interested parties across the United States and Canada.

WIL also represents CDFW on matters regarding wildlife health on state, federal, and professional veterinary committees including but not limited to: United States Animal Health Association, California Veterinary Medical Association, Western Wildlife Health Cooperative, and the Regional Emergency Animal Disease Eradication Organization.

Disease Surveillance

WIL conducts disease surveillance and health monitoring on wildlife, feral domestic ducks and geese, exotic cervids, and game farm species. The data generated is used to determine population trends, health status, demographics, and habitat use information.

Disease investigations are coordinated with agency partners, such as the U.S. Department of Agriculture, U.S. Fish and Wildlife Service, California Department of Food and Agriculture, and California Department of Health Services, other states wildlife agencies, and research partners.

Wildlife disease and mortality losses are reported by the public, agency partners, and CDFW staff. WIL collects and tracks wildlife mortality and disease information to improve our ability to monitor disease outbreaks and detect emerging health threats. Learn more!

Biological Sampling

Serum and other biological samples collected from wildlife are maintained by the WIL. Biological samples can be used to test the overall health of populations or individuals, and assists biologists in researching possible causes for die offs or illnesses within a population. These biological samples are valuable for future disease surveillance, epidemiology and genetic studies.

WIL has one of the largest archives of large mammal serology in the United States. These records are kept in databases maintained by the WIL in collaboration with other agencies and universities for complex sample processing and testing:

Zoonotic Diseases

The mission of the WIL is to investigate, monitor, and manage wildlife population health issues in California. WIL staff responsibilities include the study and surveillance of zoonotic diseases.

Zoonotic disease are caused by harmful germs that can spread from animals to humans - such as viruses, bacteria, parasites, or fungi. Zoonotic diseases are common in the United States and around the world. Learn more about zoonotic diseases in California.

Chronic Wasting Disease

Three bull elks in CaliforniaChronic Wasting Disease (CWD) is a fatal neurologic disease of cervids, that include deer, elk, and moose. This disease was first identified in wild deer and has been detected in 26 US states, Canada, Asia, and Europe.

CWD may negatively impact prey populations where it occurs and is a major wildlife conservation and management concern.

CWD has not yet been detected in California. It has the potential to spread to wild deer and elk populations in the state. CWD surveillance is a CDFW priority. Learn more about CWD and how to help!

Rabbit Hemorrhagic Disease

JackrabbitOn May 11, 2020, rabbit hemorrhagic disease virus serotype-2 (RHDV2) was confirmed in a wild black-tailed jackrabbit collected from an area where over 10 dead jackrabbits were found near Palm Springs, Riverside county. Since this initial report, RHDV2 in wild rabbits has been confirmed in the following California counties:

  • Kern
  • Los Angeles
  • Orange
  • Riverside
  • San Bernardino
  • San Diego

USDA Interactive Map of RHDV2 affected counties

This highly infectious virus affects domestic and wild lagomorphs (members of the rabbit family). RHDV2 can spread quickly and can cause high mortality in affected rabbit populations.

To date, RHDV2 has only been detected in domestic rabbits, wild cottontails, and jackrabbits, but all lagomorph species (including pikas) may be susceptible.

  • RHDV2 poses no risk to humans or other animals.
  • RHDV2 is spread through contact between infected rabbits, their meat or fur, respiratory fluids, urine, feces, contaminated soil or materials in contact with those items.
  • RHDV2 can be easily spread to new areas by moving rabbits or contaminated items, and on shoes or clothing.
  • RHDV2 may also be spread by insects and scavengers after contact with sick or dead rabbits.

Monitoring and Reporting

CDFW is tracking the geographic spread and impact of RHDV2 on wild rabbits, jackrabbits, and hares. Rabbits with RHDV2 may die quickly after infection. Blood may be present at the nose or mouth of the animal.

Help us monitor this new wildlife disease in California!

Please report sick or dead wild rabbits (2 or more) found in an area over a short period of time (3-4 days apart).

Dead wild black-tailed jack rabbitCarcass Disposal and Handling

ALWAYS use disposable glove and/or shovel if you must touch the carcass. Use 10% bleach solution (1 part bleach, 9 parts water) to spray gloves, shovel, and bottom of shoes prior to leaving area where rabbit was found to reduce risk of virus spread.

  • Burial: Carcass should be buried (3 feet minimum) when possible.
  • Incinerate: Carcass may be incinerated. Contact your local animal services agency. They may be able to dispose or incinerate carcasses. Services vary by location and there may be a charge.
  • Landfill Disposal: Carcass may be double-bagged and disposed at a landfill. Spray outer bag with 10% bleach solution. Contact the landfill to ensure they will accept submissions. Local regulations and landfill services vary by location.


White Nose Syndrome

Little brown bats in caveWhite-nose syndrome (WNS) is a disease caused by a fungus. WNS can kill up to 100% of bats in a colony during hibernation and has major conservation implications. Since 2006, the disease is estimated to have killed million of bats in the United States.

Until recently, the disease had spread slowly from its point of origin in upstate New York. In March 2016, WNS was confirmed in bats in the state of Washington. As part of a national surveillance program, samples were taken from bats at sites in northern California in 2018 and 2019.

In July 2019, the U.S. Fish and Wildlife Service and CDFW announced surveillance results suggesting the fungus that causes WNS is now present in California. Learn more!