For more than two years, the U.S. poultry industry has been battling an extremely deadly strain of avian influenza, or bird flu. The virus has driven up the price of eggs and turkeys and has moved from infecting just birds to numerous mammal species, including sea lions, rats, cats, dairy cows and, increasingly, humans.
And it shows no signs of stopping – only reaching new milestones.
The first milestone reached this month is worrisome for birds. Last week, a farm in Weld County, Colorado, with 1.3 million egg-laying chickens detected bird flu and every Federal policy, the entire herd was forced to be killed in an effort to slow the spread of the virus. These 1.3 million dead birds put the total number of chickens and turkeys that died during the outbreak at more than 100 million — more than double that number. Previous outbreaks In 2014 and 2015.
The second milestone concerns our people. In early July, bird flu was detected at an even larger farm — housing 1.78 million chickens — in the same Colorado county as the first farm. A group of few 150 workers Chickens were deployed for slaughter. They were given goggles and masks for protection, but the 104-degree heat combined with powerful industrial fans in the barns made it difficult For the gear to work effectively.
six The workers contracted the virus, making it the single most contagious bird flu event for humans in US history, more than doubling the number of Americans infected with the virus since April 2022.
About half About 900 people who became ill with H5N1 died worldwide in the early 2000s, although the strain that circulated during the outbreak proved to be milder in humans. Patients in Colorado and elsewhere have reported pink eyes, fever and cough, and the Centers for Disease Control maintains that there is a risk to the American public. is less. I spoke with four bird flu experts who generally agree with that risk assessment, but with some important caveats, which brings us to the third milestone.
Some experts have said based on this Genetic sequencing From a sick farm worker, the strain of virus that infected all those chickens and workers related to A strain that has been circulating in cattle. That means the strain is more contagious to other mammals — like humans — than a typical poultry H5N1 virus.
“I don’t think it’s a coincidence that several people were infected with this version of the virus, which has adapted to cows,” said Philip Meadis a microbiologist at Mount Sinai Health System.
That doesn’t mean a bird flu pandemic is on the horizon. For this to happen, the virus would have to evolve in such a way that it effectively transmits from person to person and causes more severe symptoms, which may never happen. But this is the diabolical nature of bird flu Very unpredictable. Tom Peacock, a virologist fellow at the Pirbright Institute, which researches cattle diseases, said the risk was low “until suddenly” if the virus adapted to infect humans. This increases the likelihood that this will occur in cows.
Is bird flu here to stay?
The fact that the virus has been circulating in the United States for more than two years also raises questions about whether it is endemic, meaning it spreads year-round.
Experts told me that it is already endemic in wild birds, the main reservoir of the virus, who spread it to poultry farms in the spring and fall during migration. inside EuropeWhile poultry farms have experienced a steep decline in bird flu outbreaks this year, wild birds appear to have acquired some immunity to the virus, which can occur here as well.
But the persistence of H5N1 in the U.S. during the summer months suggests that a “modest proportion” of recent poultry outbreaks, according to Peacock, appear to be caused by cattle strains, which he describes as a major shift.
“The concern here is that the virus can maintain an infection cycle involving livestock – which usually do not die or even sometimes develop symptoms similar to bird flu – creating a reservoir from which the virus can mutate adversely or cause human outbreaks. Maybe,” said Brady Pageis an infectious disease research fellow at Scripps Research Institute.
In short, we may be entering some kind of bird flu doom loop, where it has multiple reservoirs for infecting farmed birds and can adapt more easily to infect mammals.
The growing threat level is also a damning complaint by the US Department of Agriculture. sclerotic reaction to the virus, which has drawn sharp criticism from the infectious disease research community.
Bird flu first began infecting dairy cows late last year, but was not detected until late March. It took several weeks for the USDA to upload critical data about the virus. It also did not mandate routine testing of dairy cows, and did not require farms with positive H5N1 tests to report them — a move that hampered scientists’ efforts to track and prevent the spread. The agency required at least a month of testing before cows crossed state lines, and there was no active effort to test large numbers of farm workers.
The response is consistent with USDA’s respectful relationship with industry and partly explains how we got here. The USDA has resisted calls to vaccinate poultry birds because it would disrupt trade deals, and thus the industry’s bottom line. The USDA also helped create the modern factory farming system, which provides the perfect conditions for viruses to spread: hundreds to thousands of vulnerable, genetically identical animals packed together in unsanitary barns.
“We should treat a potential pandemic threat like this virus with the same seriousness that we apply to our national defense,” said Mount Sinai researcher Mead.
If we don’t, we’ll have a harder time breaking out of the bird flu doom loop. Without a strong response to contain the virus — and a transparent reflection on the pandemic risk posed by America’s meat industry — we will likely see the horrific deaths of more farmed birds, more sick cows, higher food prices and an increased threat. We spark the next epidemic.
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