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

The report is the first official inquiry to raise the possibility animal welfare activists introduced the deadly pathogen.



April 26, 2024, 9:59AM

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.

In effect, the document — an epidemiological review of outbreaks in both Sonoma County and the Central Valley poultry hotbed of Stanislaus/Merced counties — was published Wednesday by the California Department of Food and Agriculture. It provides fodder for both sides of an ongoing battle between environmentalists and representatives of the county’s agricultural industry.

Those critical of the industry, such as the organizers who gathered enough signatures to place a local anti-factory-farming ordinance on the 2024 ballot, find plenty in the report to support their views that prominent Sonoma County poultry farms aren’t doing enough to protect their birds from viruses and other biological hazards.

The Department of Food and Agriculture noted internal biosecurity concerns “at all Sonoma (infected premises).” Biosecurity refers to protective measures to prevent the spread of pathogens, including those meant to halt organic material from being transported in and out of different facilities.

The area’s commercial farmers, meanwhile, highlight a different section of the report — the one titled “Security Breaches.”

“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 (Sonoma County) premises during those incidents.”

From the start of this winter’s flu season, some in the local agriculture industry have raised the specter of trespassing demonstrators as a vector for Highly Pathogenic Avian Flu. This is the first official inquiry to cite the possibility.

Mike Weber, co-owner of Weber Family Farms and Sunrise Farms, said he was “shocked” to find security breaches mentioned in the report.

“They would never put something in a report like that unless they had serious concerns,” Weber said. “They are not a political organization. The fact they thought it was significant enough to list it right at the top, that scares the hell out of all of us. Because there’s nothing to prevent those individuals doing it again.”

Genetic sequencing from the initial Sonoma County detection this winter indicated likely introduction by wild birds, according to the state report.

After that positive test, “activists posted on Social Media that they also had ‘rescued’ chickens from another poultry premises in the area, which was the second premises where HPAI was detected; no video evidence exists. Whole Genome Sequences of collected samples from both (sites) are similar.”

The activist group Direct Action Everywhere, which relies in part on video evidence collected during unauthorized entry to poultry and livestock operations, rejected the allegation.

“As we’ve shared before, Direct Action Everywhere's biosecurity measures go above and beyond industry standards, and all of our biosecurity protocols have been veterinarian-approved,” the group said in an email, through a press representative. “Investigators quarantine away from poultry, waterfowl, and other birds for a minimum of 7 days prior to entering a facility.”

Activists making incursions shower, sanitize equipment and put on clean clothes before entering a property, the email stated. Before entering barns, they don biosecure shoe covers and full biosecurity suits — “which even Reichardt’s own workers don't do.”

Reichardt Duck Farm was the site of one autumn incursion, and the site of an avian flu outbreak.

The Department of Food and Agriculture’s investigation did reveal several contamination vulnerabilities in the operations of local poultry farms. Some of them related to cross-ownership and cross-management, raising concerns about employees moving between various facilities.

For example, “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 also pointed an instance of three Sonoma farms that “regularly sent nest run eggs (unwashed and ungraded eggs) to be processed at a fourth”; those four premises shared a closely related virus with three others in the area, the report states.

Even the collection of tissue samples, the tool underlying much of the state’s investigation, came under scrutiny. Someone collected samples at two different farms on the same day, the report says. Both turned up positive.

An additional flaw cited by the department involved employees participating in depopulation and disposal efforts at one site, then working at another site that subsequently registered an infection with a closely related gene sequence.

Mike Weber believes that event stems from his facilities, and he points to it as a flaw in the epidemiological report.

“We had crews from one site working to depopulate on another site,” Weber said. “We moved them back, but it was during a fallowing period by the employees. They didn’t go straight from one site to another. So there was no chance to bring the disease in their clothes or on their body.”

The confusion, according to Weber, stems from the Department of Food and Agriculture’s simplified questionnaire, which asked if certain things had occurred without allowing nuanced explanations.

Generally, Weber said, the local farm industry follows best practices.

“I’m sure there’s something we could have done that would have changed the impact here,” he said. “But from a biosecurity standpoint, no. Except for hardening our buildings to intruders.”

Even as it laid out the possibility of contamination by either intruders or farm employees, the state agency noted that, “There is no absolute evidence that any of these risks caused such transmission; the sequence subcluster (sites) could have had common source introductions of virus, given the proximity of the premises.”

Since the start of the global 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.

California has been hit hard. Wild bird populations have long been viewed as a central link to outbreaks in commercial flocks, and the wetlands and open fields of the North Bay are popular stopping points for waterfowl migrating between Canada and Mexico on the Pacific Flyway. About 520,000 birds traveled through Sonoma County each night in the first half of November, the state researchers estimated.

The recent wave of infections has been particularly devastating here, where egg and poultry production constitutes a $50 million industry.

The two sides of the chasm agreed on the importance of one area of investigation, though for different reasons: an examination of the effects of wind in spreading Highly Pathogenic Avian Flu.

As part of the report, the Department of Food and Agriculture cited a Dutch study that used statistical modeling to estimate that wind contributed 18% to the total amount of avian flu transmission among poultry farms.

Weber, the local producer, took this as evidence that there was little Sonoma County poultry farmers could have done to prevent the onslaught of the virus.

“From the very beginning, this has spread like a wildfire, and we have believed it was coming from the wind,” Weber said. “That was the key take-away I saw. We could have had better biosecurity, and it wouldn’t have had any impact.”

To Direct Action Everywhere, on the other hand, this was more evidence of poor practices on farms.

“The report also details the threat that wild birds and wind both pose to commercial poultry operations. Reichardt Duck Farm’s structures are not equipped to protect against these threats,” they wrote. “The barns have mesh walls with gaping holes that would allow not only contaminated debris, such as feathers and feces, to enter the structures, but even wild animals.”

In addition to the research findings, the California State Veterinarian requested that recommendations be included with the findings.

That office urged farmers and investigators to prioritize dead birds for viral sampling.

Focusing too much on randomly selected healthy animals “can lead to delayed detection, which could in turn have resulted in higher viral loads in the environment after depopulation,” the report states.

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

What you need to know about avian flu

What is avian flu?

Avian influenza, also known as bird flu, is a disease caused by Type A influenza viruses commonly found in bird populations.

How does it spread?

Avian flu viruses occur around the world and are commonly spread among aquatic birds, especially during seasonal migrations. It spreads directly through airborne transmission but can also be transmitted when fecal matter from an infected bird comes in contact with feathers, feed, water or soil. It can also be introduced to poultry populations through contaminated shoes, gloves or equipment.

How serious is it?

Most strains of bird flu are relatively harmless to their natural hosts, and often cause no symptoms. However the virus can mutate into what’s known as highly pathogenic avian influenza virus, which is highly infectious and often deadly. The type that has been detected in Sonoma County has been identified as highly pathogenic avian influenza.

Is there a risk to humans?

While the disease can be transmitted to humans most avian influenza viruses result in no symptoms or only mild illness. Some strains, however, can potential be fatal to humans, although cases are rare. Humans are typically infected through close contact with infected birds, bodily fluid droplets, or through bird droppings. Wearing goggles and face masks around bird populations can reduce the risk of infection.

What is the impact to the poultry industry?

When avian flu is detected in a commercial poultry operation, state and federal guidelines require that the entire flock be euthanized to prevent the spread. Since the start of the outbreak in February 2022, more than 90 million birds have been affected in the United States, resulting in higher prices for eggs, chicken, turkey and duck for consumers.

(Source: U.S. Centers for Disease Control and Prevention; European Centre for Disease Prevention and Control)


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