by The bird flu was detected among chickens in Texas and Michigan, following news of the virus infecting livestock and then humans for the first time in the US and potentially causing supply chain issues.
The developments have resulted in a heightened focus on the potential risks of the virus, especially in the wake of the devastating coronavirus pandemic. But experts say there is little chance of human-to-human transmission at this point.
Cal-Maine Foods, the largest producer of fresh eggs in the US, has temporarily halted production at one facility in Texas and is culling 1.6 million hens and 337,000 chickens – 3.6% of its total flock – after contracting the highly pathogenic virus to discover among his domesticated birds. .
“These are tough times for dairy farmers and poultry farmers,” said Lewis R “Bud” Dinges, Texas state veterinarian and executive director of the Texas animal health commission.
Outbreaks like this could affect the price of poultry and eggs, especially if the virus continues to spread in domesticated flocks – like the 2022-23 outbreak which saw the price of eggs rise by 70%. Continued spread among chickens could also threaten the production of the flu vaccine, which relies on 140m eggs a year to hatch inoculants.
The CDC issued a health advisory last Friday, recommending that doctors be on the lookout for possible bird flu among patients, especially those who are in frequent close contact with birds and animals.
Anyone who comes into contact with birds and livestock, including agricultural workers, hunters and backyard farmers, should wear protective gear and follow strict hygiene standards. They “just need to pay extra attention to biosecurity and cleaning and disinfection”, said Dinges. “Make sure they wash their hands and wear protective clothing and leave their clothing at the facility where they work – clothing and footwear if possible.”
A prisoner slaughtering infected flocks in Colorado became the first person in the United States to be infected with bird flu in 2022.
On March 20, Minnesota reported that baby goats were sick with bird flu, marking the first time the virus has been found in livestock. A day later, the virus was also found among the cows. Cows in North Carolina tested positive for bird flu on Wednesday, bringing the number affected to 21 herds in seven states.
Genomic sequencing showed that the exposure to cows did not appear to make the virus more transmissible to humans this time, so the risk of sustained human-to-human transmission remains low, Seema Lakdawala said. , associate professor of microbiology and immunology at Emory University. School of Medicine.
“Transmission of influenza viruses in humans requires many different variables to align properly, and the current H5N1 viruses do not have all the right parameters to spread between humans,” she wrote in an email.
“However, the more the virus sheds from birds to other hosts such as cattle, foxes, seals, etc. the more likely it is that the virus will change and acquire properties that allow for successful human-to-human transmission lead to it.”
Avian influenza is an “emerging disease” among livestock, Dinges said, “and there’s a lot we don’t know about the pathogenesis of cows themselves. We’re still kind of learning as we go here.”
It is not clear how the flocks encountered the virus, but the genomic sequences are very similar – pointing to a single introduction, probably from a dead bird, that spread within the flocks rather than several introductions over time.
The dairy cow outbreak could lead to local shortages, but is currently unlikely to cause national or regional shortages or price increases, said Tinglong Dai, a business professor at Johns Hopkins University’s Carey School of Business. That’s because the United States is in its high season for milk production.
“In the spring and summer, you usually have a higher yield than in the winter,” he said. “Suppose this happened in the fall or winter: the impact on the supply chain would be much greater.”
If the outbreak among cows continues to fall, it could affect supply and prices. In the meantime, affected cows are being isolated until their illnesses disappear.
On the other hand, chickens usually die from the virus, so producers kill them as soon as the virus is detected.
“The most effective way to stop the spread is to kill the chickens,” Dai said. That means this outbreak could have a bigger impact on poultry and egg prices than milk and cheese.
The manufacturing process for flu shots also relies heavily on eggs, and past egg shortages have led to vaccine shortages. So far, no vaccine makers have reported shortages.
“Just if the situation continues – if the infection spreads, again, we have to monitor closely,” said Dai. “This also depends on how this unfolds in the coming days.”
Scientists are sounding the alarm to keep farmers and other agricultural workers safe, and to continue to monitor the spread of the virus.
For example, it’s unclear how common it is for bird flu to spill over from birds to animals, Lakdawala said. “Right now, in the United States, it’s from examining animals that are found sick or have died.”
If the virus is quietly spilling over into other animal hosts that don’t get very sick or die – as with red-tailed deer and Covid – scientists don’t know about it. That’s why they need more funding to monitor viruses like the flu, Lakdawala said.
“This is a gap that we must try to fill, but it is difficult to do without more resources and investment in large-scale surveillance programs.”
