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Bird flu: time to rethink farm surveillance?



Bird flu: time to rethink farm surveillance?


The spread of bird flu to dairy cows, together with the discovery of virus fragments in 20 percent of retail milk samples, has turned an outbreak that has long plagued poultry farmers into a source of stress for consumers. The situation is fraught with uncertainty as researchers’ understanding of the virus evolves along with the virus itself. On one point, however, the evidence is in: the US needs better surveillance of pathogens on large livestock farms.

As of this writing, the Centers for Disease Control and Prevention has done so reported confirmed cases of the highly pathogenic avian influenza virus A(H5N1) in pets in nine states. The virus is “highly pathogenic” for birds and many other animals sealsbut for now, CDC says the risk of infection for the general public “remains low.”

Epidemiologists have been working on this for a long time concerns expressed that a “bird flu” strain could adapt to infect humans and cause another pandemic. When an H5N1 bird flu virus was first discovered in 1996, that’s what happened infect almost a thousand people with a mortality rate of more than 50 percent. In 2009, a bird flu virus spread to pigs:swine flu– caused an estimated 12,469 deaths in the United States. The A(H5N1) virus has not yet resulted in a confirmed human death or serious illness. However, it is lethality in the wild populations, and its widespread transmission among many species mammalsincluding dairy cows, have raised concerns.

Exposure to infected dairy cows is believed to have caused the most recently confirmed case of human illness, reported by Texas officials on April 1. A previous case from 2022, in Colorado, involved exposure to infected poultry. Both cases were reportedly mild. But flu viruses are notorious for their shape changes. The risk of A(H5N1) turning into a pathogen that spreads easily between people, with more serious health consequences, warrants a robust surveillance program to track where the virus is emerging, how it is changing, and under what conditions it is spreading.

Unfortunately, we are missing a crucial part of that supervision: on the farm. Authorities from USDA’s Animal and Plant Health Inspection Service (APHIS) have issued an order order requiring A(H5N1) testing in dairy cattle crossing state lines. But we need a broader sampling program. In addition to understanding all cows that remain in their home states, federal authorities should also take samples from other species, especially pigs, which many experts consider a critical bridge between flu viruses that kill birds and humans.

USDA has the authority to require testing, at least for animal diseases. Federal statutes give the agency the authority to “conduct operations and measures to detect, control, or eradicate any pest or disease of livestock (including the drawing of blood and diagnostic tests of animals), including animals in a slaughterhouse , livestock farming or other point of concentration.” 7 USCA § 8308. Concentrated swine and other concentrated animal feeding operations (CAFOs), i.e. the source of the big majority of all livestock and animal products consumed in the United States are likely to fall under “other concentration points.” So it appears that USDA would be on solid legal ground if it were to implement an A(H5N1) testing requirement for swine farms. The law requires USDA to compensate farmers for testing costs, but if the costs prevent USDA from conducting critical surveillance to prevent the next pandemic, Congress should ask for more money.

The pork industry might protest that A(H5N1) is not a disease that affects pigs, and that testing pigs for the virus would actually amount to a public health surveillance program. To the extent that this characterization is accurate, it is problematic because the federal government does not have the authority to require or itself conduct public health surveillance on farms. Why do federal officials have the authority to detect animal diseases on farms but not human diseases? Congress must address this absurd discrepancy.

Aside from bird flu, the lack of authority of public health officials to conduct basic epidemiological surveillance on farms is impacting food safety. Recent investigations in which livestock industries refused to cooperate with federal requests for microbiological sampling include Salmonella outbreak linked to porkand an outbreak of E. coli O157:H7 infections linked to romaine lettuce probably infected with manure from an adjacent pasture that was home to more than 100,000 cattle. Whole-genome sequencing of samples from the pig and cattle farms involved in these outbreaks, and countless others, may have provided important clues about the origins of the outbreaks and how to avoid similar food safety disruptions. But under the current regulatory regime, livestock producers simply have no incentive to submit to sampling requests.

Fortunately, efforts are being made to solve this problem. My organization, Consumer Federation of America, has joined other consumer advocates to support the Extensive Food Safety Research Act. The accountnow approved by ten members of Congress in both chambers, would give the U.S. Food and Drug Administration authority to conduct microbiological sampling at CAFOs for the purpose of investigating a foodborne illness outbreak or any other public health need.

So far, the industry hasn’t had to seriously grapple with requests to explain its opposition to seemingly common-sense measures like the law. But as new pathogens such as the A(H5N1) virus emerge, the demand for reform will increase. Rather than reflexively stonewalling efforts to increase transparency, livestock industry leaders should join the conversation and help guide the development of effective pathogen surveillance protocols on farms.

In the meantime, consumers can protect themselves from the A(H5N1) virus in food by avoiding it raw milkand practicing the “four core” Food Safety Practices for Meat and Poultry, Including Eggs. For employees, the CDC has issued guidelines about the use of PPE.

With any luck, the A(H5N1) virus will remain harmless to humans and will soon disappear from the public eye. However, we should not wait until a crisis breaks out before building critical public health infrastructure. That infrastructure includes policies to effectively monitor farms for human disease-causing pathogens.

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