Avian Cholera Cause of Recent Bird Deaths

Jan. 11, 2008

Contact: Dan Yparraguirre, Wildlife Programs Manager, (916) 445-3685
Melanie Weaver, Wildlife Programs (916) 455-3717
Mary Salas Fricke, Bilingual Public Information Officer, (916) 322-8911

Avian cholera has been identified as the cause of recent waterfowl die-offs in northern and central California according to Department of Fish and Game (DFG) wildlife officials.

“Avian cholera is a very common occurrence in waterfowl during the winter months in California, especially during cold spells and fog,” said Dan Yparraguirre, Wildlife Programs Manager. “The disease is lethal to waterfowl and other water birds, and does not affect humans.”

Bird die-offs have occurred in Del Norte County, Humboldt County, Stanislaus County and at the Sacramento National Wildlife Refuge (NWR) Complex in Glenn County, the San Joaquin River NWR in San Joaquin and Stanislaus Counties, and the Butte Sink NWR in Butte and Sutter Counties. DFG submitted samples from the affected birds to the California Animal Health and Food Safety labs for necropsy and confirmation of the diagnosis. The samples also were tested routinely for avian influenza and were negative.

Avian cholera (not related to human cholera) is one of the most common diseases in North American waterfowl and results from infection with the bacterium Pasturella multocida. It spreads rapidly from bird-to-bird and can kill thousands of birds in a single incident. A bird infected with avian cholera dies quickly.

More occurrences are possible as the winter months continue, especially in the Central Valley which is a primary destination for wintering waterfowl. DFG and the US Fish and Wildlife Service are working closely in responding to bird die-offs, and are poised to rapidly investigate and collect samples for testing if other die-offs occur. The public should report dead wild birds by calling (877) 968-2473 or on-line at www.westnile.ca.gov.