In the Central Valley the lack of wastewater testing for bird flu is a blind spot

As the H5N1 bird flu virus continues to wreak havoc on California's dairy and commercial poultry flocks, a Central Valley state official is raising concerns about the state's lack of wastewater monitoring.

State Sen. Melissa Hurtado (D-Sanger) is frustrated by what she says are gaps in tracking the spread of bird flu in the Central Valley, where many of the state's most vulnerable populations — dairy and poultry workers — live and work.

“If you're tracking an animal-to-human disease, you want to look in rural areas, like Tulare County where there are more cattle than people — yet there's no wastewater testing anywhere south of Fresno Valley,” Hurtado said.

As of December 30, 37 people in California have tested positive for H5N1; all but one was a milkman. In addition, more than two-thirds of the state's dairy herds – 697 – have been infected, as well as 93 commercial or backyard poultry flocks, totaling nearly 22 million birds.

On December 18, Gov. Gavin Newsom declared a state of emergency after the virus jumped from Central Valley dairy herds to Southern California dairy cows, despite quarantine restrictions designed to stop the spread.

The virus, which is carried by migratory birds and wildlife, has been found in contaminated water sources across the region, including in Los Angeles, San Francisco and San Jose.

However, sampling is limited in the Central Valley, where most human cases are reported and risk is high. Indeed, avian influenza wastewater sampling is not available in some of the high-risk counties, including Tulare and Kings.

Why the current assessment is not good enough

Taking samples of contaminated water helps public health officials track the spread of the virus. It has been a strategy employed by officials during the COVID-19 crisis to monitor the spread of the coronavirus. In California, officials used contaminated water to predict waves of infection and how much the virus was circulating among people.

In California, health officials say they are monitoring 78 sites in 36 counties for a range of pathogens; in all but two domains they said they wanted bird flu.

In an email to The Times, state officials said the Cal-SuWers Network monitors six locations in the Central Valley, including Kern, Merced, Stanislaus and San Joaquin counties.

According to the Centers for Disease Control and Prevention, the most recent sample from Kern County was sent on December 7, and it was positive for the virus.

It's a big blind spot in the state's surveillance system, state officials admit, but note they have little control over it.

“The availability of wastewater monitoring in the area … requires the participation of utilities, which is voluntary,” said Ali Bay, a spokesman for the federal agency. “Competition for priorities and resource limitations can reduce a [utility’s] the power to participate.”

Tulare County and Kings County lead the nation in the most crimes, according to statistics released by each county.

Laura Flores, spokeswoman for the Tulare County public health department, said the county's private wastewater treatment plants have chosen not to participate in the state's monitoring program. Tulare has 18 reported cases, the most of any county and nearly half of the entire state.

Everardo Legaspi, deputy director of the Kings County public health department, did not provide an exact number of reported cases to the state, other than to tell The Times he knew of “less than 10.” The district has not been able to participate in the wastewater testing program since October due to staffing shortages, he added, but the district is working to start wastewater collection and expand it to other sites in the district.

For months, experts have worried that public health authorities have been complacent in their response to the outbreak, and that public safety has taken a back seat to agricultural interests. It was last month that the US Department of Agriculture began a program to test the virus in the nation's raw milk — nearly a year after experts believed the virus had spread to cows, and after more than 900 dairy herds and 60 people were infected. .

“I think people continue to minimize this outbreak and this virus,” said Rick Bright, a virologist and former head of the US Biomedical Advanced Research and Development Authority. “Our government officials are not doing the thorough investigation they should be doing.”

Even after the USDA's announcement about the new bulk milk inspection program, only 13 states were included in the initial release; many, including California, Colorado and Michigan, were already testing their milk.

And the incoming Trump administration has threatened to withdraw the US from the World Health Organization, a move that will blind the US and the rest of the world to the movement of this virus. Although the Biden administration announced on Thursday that it is making an additional $306 million to stop the outbreak of bird flu in humans – money that will be distributed before he leaves office later this month.

“I don't think the right questions are being asked to understand this bird flu,” said Hurtado. “In large part it's because there's just a lack of guidance from the feds.”

What can we learn from bird flu monitoring if we do it right?

To be sure, finding bird flu in contaminated water does not necessarily mean there is a human outbreak of the virus.

Unlike COVID-19, mpox or seasonal flu — which when found in contaminated water can indicate human infections — positive samples of bird flu may come from a variety of sources, including unpasteurized milk. That's because the method used to sample bird flu in contaminated water looks for traces of the virus, not the whole virus.

That means the tests may be picking up bits of the virus that are no longer active, such as those found in unpasteurized commercial milk.

“I don't think we really know what it means,” said Richard Webby, director of the World Health Organization's Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds. ”How much milk is poured in the urban area? We know we can find… high loads in supermarket milk. I actually don't know what supermarkets do with expired milk.”

It may also come from raw milk or raw meat. Or even contaminated products from wild birds and mammals, where the virus is currently circulating.

Since the outbreak began, California officials have detected the virus in wild birds such as pigeons, white-faced ibis, and turkey vultures, as well as wild mammals including mountain lions, raccoons and skunks.

In addition, it is possible that people are shedding the inactive virus in the wild, said Alexandra Boehm, a professor of civil and environmental engineering at Stanford University and the principal investigator and director of the WastewaterSCAN program.

The battle to improve the system

Regardless of what the samples show, they provide evidence that the virus is circulating somewhere in the environment.

And the fact that health and water officials in some regions of the state are deliberately not looking at it is another example of the government's failure to stop the disease and track its spread, said Bright.

“The virus is emerging quickly… Without full participation in surveillance and testing programs, coupled with full and timely transparency, we will always be the cause of this virus,” said Bright. “Our ability to get ahead of it will be hampered without full cooperation and collaboration at the federal, state, local and community levels.”

For Hurtado, the situation is also personal.

He said his father and nephew, who live in the Central Valley, showed symptoms of bird flu earlier this year, but no tests were available to confirm his suspicions.

Her father contracted a virus that nearly killed him and included severe muscle and body pain, a symptom of bird flu. Her 7-year-old nephew, who lives in Sanger, a city with a large poultry production area, recently had an unusual immune response to the virus, and had red, swollen eyes, which is a symptom of the H5N1 virus. His doctors don't know what caused the reaction.

Despite showing symptoms, he said, no one was tested for bird flu – but he suspects they have it. Dairy farmers, workers and family members also told The Times they believe the state's reported numbers may be low, as some workers may not report being sick for fear of losing their jobs.

“I don't have any science or information to back that up, but my heart tells me that my father and nephew have bird flu,” she said. “Both are affected by a serious illness from an unknown virus.”

His experience has motivated him to push the state for answers in tracking the spread of the virus. He asked the state Department of Health about the lack of testing in the Central Valley but said he has not yet received a clear answer.

Hurtado also emphasized that testing should be increased in high-risk communities. Despite some screening of vulnerable people, including dairy and poultry workers, the state does not provide a comprehensive screening method for agricultural communities.

Hurtado, whose district includes much of the Central Valley, said he intends to propose legislation that would expand the state's wastewater monitoring program to include sites in underserved and high-risk rural communities. The legislation would also develop a methodology for identifying priority sites based on health risks, population density and socio-economic factors.

Hurtado is concerned about communities like Sanger, his hometown. There is a poultry farm, one of the biggest employers in the city and the region, which has been hit hard by bird flu.

Since the end of October, a dozen commercial poultry farms in Fresno County have been infected with the virus, resulting in the deaths of more than 1.5 million birds.

You've heard stories of workers losing hours of work as animals get sick and chicken farms are completely deserted. The price of eggs has also increased due to this disease.

“I think we could have done a lot earlier,” he said. “But we are here, and we should be able to improve where we failed.”