FRESNO, Calif. – Federal health officials have changed their guidance on testing for highly pathogenic avian influenza.
The virus, known informally as bird flu, ravaged poultry flocks for years before being found this spring in cattle and, most recently, humans. In California, the virus has been confirmed in 21 dairy workers — the largest caseload of any of the six states where human cases have been reported — as well as 259 dairies.
Until recently, the Centers for Disease Control and Prevention recommended testing only those farmworkers who showed flu symptoms. As of last Thursday, however, the CDC changed their guidance to urge any worker to be tested after contact with an infected animal, regardless of symptoms — especially if they were not wearing proper personal protective equipment (PPE).
The update follows a new study, published last week in the CDC’s Morbidity and Mortality Weekly Report, that suggests the virus is more common among farmworkers than previously thought.
The study, which tested the blood of 115 farmworkers in Michigan and Colorado, found antibodies representing a previous infection of the virus in 7% of study participants. All of them either milked cows or cleaned milking parlors; only half of those recalled feeling any symptoms of illness around the time they worked with infected cattle.
Elizabeth Strater, spokesperson with the United Farm Workers union, said undercounting is likely in California, too.
“We’ve heard from farmworkers and community members and veterinarians that symptomatic workers are clearly still working,” she said.
As for why, Strater said the state requirement for five days of paid sick leave per year won’t cover the 10 days of isolation required by public health agencies. Plus, some workers fear retaliation from their employers for reporting their illness.
Strater said she hopes mandatory testing could reduce at least some of those barriers.
“When you level the playing field and say, ‘OK, everyone is going to get surveillance testing,’ that means it no longer requires the worker to step forward [and] defy the spoken or unspoken wishes of their employer, to get tested,” she said.
Although workers compensation can cover a significant portion of farmworkers’ salaries, Strater said many are leery of providing personal information to the government – especially if they’re undocumented.
Tricia Stever Blattler, Executive Director of the Tulare County Farm Bureau, said she’s heard of another issue that could prevent workers from taking advantage of workers compensation claims: the specialized nature of testing.
“The dairy producers that I've talked to have been directed to send their workers directly to one medical facility” for testing, she said. One of those producers then told her, “‘I don't mind following that protocol, but I have my own workers comp medical clinic that would request that I send my worker there, and now I'm in conflict because I'm supposed to be following the county's public health department’s guidance.’”
As many as 17,000 dairy workers are employed in California in any given year. Stever Blattler speculated that testing them on a widespread scale – while maintaining milking schedules – would be a tall order.
Some media outlets have reported that some dairy operators in other states have been reticent to cooperate with public health officials. While Stever Blattler acknowledged that with hundreds of dairy operators in Tulare County, there is bound to be a spectrum of tolerance for working with the government, she’s certain that most dairy farmers want to be on the right side of this health emergency.
“I've only heard positive things,” she said. “I've heard that they're trying to adhere to the guidelines, they're trying to get the PPE out to all their workforce, they're trying to make sure their workers know what to do if they come up with symptoms, and they’re certainly trying to protect cow health.”
Dr. John Zweifler, a consultant for the Fresno County Department of Public Health, agreed.
Public health officials, he said, “have really made a great effort to work collaboratively with the dairy farms, so that we are working together to provide a safer working space for four farmworkers—and at the same time, doing whatever we can to support those dairy farms that are really going through a really difficult time right now.”
Although cases among people have all been relatively mild, generally marked by conjunctivitis, he warned the virus could change course if it’s not contained.
“The concern, of course, is that it could potentially mutate and cause more significant illness,’ he said. “You have to balance the fact that currently it is relatively mild with the concern that the potential for possible mutations…could lead to more serious disease in the future.”
As for how farmworker testing could logistically be rolled out, the California Department of Public Health issued a statement to county health departments saying that further details will be forthcoming.
“We are reviewing the CDC’s updated recommendations and working with local public health departments to determine what resources will be needed,” the statement reads. “Our overall focus continues to be on minimizing illness in humans by educating farms and workers on preventive measures such as wearing protective equipment, promoting health checks for exposed workers, and providing timely testing and treatment.”
