Chronic Wasting Disease Detected in California Deer and Elk

For the first time, Chronic Wasting Disease (CWD) has been confirmed in California’s deer and elk populations, raising concerns about wildlife health across the state. The California Department of Fish and Wildlife (CDFW) reported the detection in samples collected from two deer—one in Madera County near Yosemite Lakes and another in Inyo County near Bishop.

CWD is a fatal neurologic disease that affects cervids, including deer, elk, moose, and reindeer. It causes progressive brain damage that leads to death, and there is no known treatment or vaccine available. The disease has been detected in 34 states and several Canadian provinces, and even in parts of Scandinavia, reflecting its widespread impact on cervid populations.

The infected deer in Madera County was found dead from unknown causes, while the one in Inyo County was discovered after a vehicle collision. The findings suggest that CWD may have been present in the state for some time due to the disease’s lengthy incubation period, which can span months to years.

CWD is transmitted through prions, abnormal pathogenic agents that are resilient in the environment, potentially contaminating soil and plants. Infected animals can excrete these prions before symptoms appear, complicating efforts to control the disease’s spread. Dr. Brandon Munk, CDFW’s wildlife veterinarian, emphasized the challenge, noting that prions can persist in the environment for years, making it very difficult to prevent or control the spread once introduced.

Symptoms of CWD include weight loss, lack of coordination, listlessness, drooling, excessive thirst or urination, and behavioral changes. These signs eventually lead to rapid death once they develop. The disease poses a significant risk to wildlife, and while there is no known link between CWD and human disease, health organizations recommend preventing prion diseases from entering the human food chain.

In response to the outbreak, CDFW has been conducting lymph node sampling and testing since 2000, with over 6,500 deer and elk tested. Enhanced surveillance efforts have been in place since 2018, with assistance from hunters, taxidermists, and meat processors.

The public is urged to report any sick deer or elk and hunters are encouraged to have their harvest tested for CWD. You can report them here.