by There is a “strong possibility” that bird flu has been spreading on US cattle farms since last year, according to a new analysis, prompting questions about America’s pathogen surveillance capabilities.
Last month, the H5N1 strain was seen in cows for the first time, shortly before a human case was discovered in Texas. The virus, which has killed thousands of birds worldwide since 2020, was later identified in 36 dairy herds across eight US states, raising concerns about its ability to infect mammals.
US health officials released genomic data taken from infected cattle on Sunday, after previously saying there is evidence that H5N1 is spreading among cows. However, an analysis of the data now shows that the virus could be circulating in the animals from the end of 2023.
“It seems to me that there is a strong possibility that this has been spreading in cattle for months under our noses, even before the first inkling that there might be something new in February,” said Professor Michael Worobey, a biologist at the University Arizona produced. the analysis.
“This common ancestor may have existed around the end of 2023,” he said on X (formerly Twitter). “It is possible that the common ancestor was in cattle, with only one disturbance of cattle and subsequent spread. But we cannot rule out multiple jumps, later, from a mostly avian reservoir.”
The virus’s apparent ability to spread between cows is significant because it gives it more opportunities to evolve to better infect other mammals, possibly including humans.
Of particular concern is whether H5N1 could now infect pigs, which are often called ‘mixing vessels’ for flu and make it more likely that the virus could spill into humans.
There are also unconfirmed reports that the virus has jumped from cows back to birds, highlighting the potential threat of recombination – when different viruses join together and mix their properties. together to create a new strain.
Dr. Gerlad Parker, Associate Dean for Global One Health in the College of Veterinary Medicine & Biomedical Sciences, said the cattle outbreak highlighted the need for improved pathogen surveillance in the US.
“The virus is more widespread than reported … and was probably circulating in cattle for some time before it was identified in February, and it also tells us that we need to modernize surveillance systems in a way that integrates health animal and human,” he said.
Questions about the cattle industry
Currently, the World Health Organization has stated that the risk to humans is still considered low, but that surveillance efforts must be maintained – which may be hampered by the lack of accessible information released by US Department of Agriculture (USDA), experts say.
After increased pressure, USDA released 239 genetic sequences of the H5N1 flu from poultry, wild birds, and dairy cows on Sunday afternoon, which scientists hoped would provide new clues about the spread of the virus.
However, the data was released without any information indicating where and when each animal was infected.
“It creates unnecessary delays and probably doesn’t have a complete set of all the sequence data that USDA has collected so far,” said Dr. Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan, who was involved in the analysis. by Professor Worobey’s staff.
“It’s important to figure out how this got into the cattle and the mechanism by which it’s spreading in them, but the incomplete metadata is ultimately a hindrance to that goal.”
Some believe USDA is not providing information to protect the commercial interests of the cattle industry.
Michael Osterholm, director of the University of Minnesota Center for Infectious Disease Research and Policy, said: “The USDA is primarily focused on protecting the animal production industry, and I think that’s a short-term goal, but a long-term mistake.”
At this stage, it is also unclear what investigations the USDA has conducted, clouding any understanding of how the cows became infected, Mr. Osterholm said.
In another development, the American Association of Veterinary Practitioners, a non-profit group of veterinarians, issued a statement last week urging government agencies, diagnostic laboratories, and federal agencies to refer to the virus in cattle as ‘Bovine Influenza Virus A’, in which instead. of H5N1.
In a public letter, the organization said this is because they believe it is important for the public to understand the difference in order to maintain confidence in the safety and accessibility of beef and dairy products to consumers,” slamming a move as “unscientific . and dangerous” by virologists.
The Telegraph reached out to the USDA for comment but did not receive a response.
However, a spokesman said Journal stat: “USDA is committed to the timely and transparent release of information related to the outbreak as it becomes available. We will continue to work to provide timely and accurate updates to the public, our stakeholders and the scientific community as we learn more.”
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