State report on Sonoma County avian flu outbreak focuses on breaches in biosecurity

Apr. 26—A newly published state investigation into Sonoma County's avian flu outbreak cites a number of farm management practices that might have enabled spread of the virus this winter — and raises the possibility animal welfare activists introduced the deadly pathogen during incursions onto two bird farms in October and November.

The report by the California Department of Food and Agriculture is the first official inquiry to cite those incursions by demonstrators as potential culprits in the local outbreak, which has affected at least 10 commercial farms and forced the destruction of at least 1.2 million chickens and ducks.

"Animal sanctuary activists were videoed trespassing inside poultry barns and removing ducks on the nights of 10/24/23 and 11/14/23; decreased egg production was noted 8 days after the 2nd illegal entry," the state agency wrote. "Given the high number of wild birds migrating through the area at that time shedding virus into the environment, as well as the egregious nature of these biosecurity breaches, it is plausible that virus was introduced into the index Sonoma premises during those incidents."

California HPAI Epidemiology Investigation: Final Summary Report.pdf

The state Department of Food and Agriculture did not address the question of intent.

The agency also noted internal biosecurity concerns "at all Sonoma (infected premises)." These included issues related to cross-ownership and cross-management, raising concerns about employees moving between various facilities.

"In the Sonoma cluster, two premises share ranch managers, who were supposed to shower, change clothing, and wait 24 hours prior to entering the next premises; it's not known if this company policy was always adhered to," the report states. "In another situation, two employees were discovered to be cohabitating which was against the companies' policies."

The state report summarized an epidemiological investigation of the winter's avian flu outbreaks in two California regions, including Sonoma County.

Since the start of the outbreak in February 2022, more than 90 million birds have been affected in the United States. Most of those were healthy birds, euthanized on commercial farms to prevent further spread.

The wetlands and open fields of the North Bay are popular stopping points for wild waterfowl migrating between Canada and Mexico, and wild bird populations have long been viewed as a central link to outbreaks in commercial flocks.

The recent avian flu outbreak has been particularly devastating in Sonoma County, where egg and poultry production constitutes a $50 million industry.

This is a developing story. Please check back for updates.

You can reach Phil Barber at 707-521-5263 or phil.barber@pressdemocrat.com. On X (Twitter) @Skinny_Post.

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