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ITHACA, N.Y. — Recently, researchers have documented bird flu mutating in a way that allows it to spread to cows. In a startling development that’s causing ripples through the scientific community, a new study has uncovered evidence that bird flu is now spreading among other mammals as well.
This isn’t just any flu — it’s the highly pathogenic avian influenza H5N1 – a strain that’s been making headlines for its devastating impact on bird populations. Now, it seems, the virus has found a new home in dairy cattle, raccoons, and even cats — crossing species at an alarming rate.
Let’s break down the findings from the report in the journal Nature. For years, scientists have known about bird flu jumping from birds to humans occasionally. However, what’s happening now is different and potentially more concerning. The virus has made its way into dairy herds in several U.S. states, and now new evidence shows it’s moving from cows to local cats and at least one raccoon.
“This is one of the first times that we are seeing evidence of efficient and sustained mammalian-to-mammalian transmission of highly pathogenic avian influenza H5N1,” says Diego Diel, an expert in virology from Cornell University’s College of Veterinary Medicine, in a media release.
In simpler terms, the bird flu virus is now passing between mammals easily and consistently. This is a big deal because viruses can change quickly when they start infecting new types of animals. Each jump to a new species is like a roll of the dice – there’s always a chance the virus could become better at spreading or causing more severe illness.
Now, before we all start panicking, it’s important to note that the researchers haven’t found any changes in the virus that would make it more likely to infect humans or spread between people. However, the fact that it’s now moving between mammals is definitely raising eyebrows in the scientific community.
So far, there have been 11 human cases reported in the U.S. since April 2022. Thankfully, these cases have been mild. Interestingly, four of these cases were linked to cattle farms, while seven were connected to poultry farms. The most recent outbreak involved four cases in Colorado, and the researchers suspect these infections came from dairy farms in the same area. While the virus can infect people, it doesn’t do so very efficiently at the moment.
“The concern is that potential mutations could arise that could lead adaptation to mammals, spillover into humans and potential efficient transmission in humans in the future,” Diel warns.
This situation highlights the importance of keeping a close eye on the virus as it spreads through animal populations. The U.S. Department of Agriculture is offering free testing for H5N1, which is crucial for catching outbreaks early. If a farm tests positive, quick action – like quarantines and increased biosecurity measures – can help stop the virus from spreading further.
Let’s rewind a bit to understand how we got here. The current wave of H5N1 infections in the U.S. started in January 2022. Since then, it’s led to the deaths of over 100 million domestic birds and thousands of wild birds. The jump from birds to cattle was first noticed by scientists at Cornell and Texas A&M, who detected the virus in dairy herds.
The cows likely caught the virus from wild birds, and it’s making them sick in various ways. They’re eating less, having digestive issues, struggling to breathe, and producing less milk that looks abnormal.
One particularly concerning finding is that the virus seems to have a fondness for infecting cows’ mammary glands, leading to high levels of the virus in their milk. Don’t worry about your morning cereal, though — pasteurization kills the virus, keeping our milk supply safe.
The researchers used some pretty high-tech methods to track how the virus was spreading. They looked at the genetic makeup of virus samples and used computer models along with good old-fashioned detective work to piece together the outbreak’s story. They found that infected cows from Texas spread the virus to healthy cows when they were moved to a farm in Ohio.
However, it’s not just about cows now. The virus also infected cats, a raccoon, and wild birds found dead on affected farms. The researchers think the cats and raccoon probably got sick from drinking raw milk from infected cows. As for the wild birds, they might have picked up the virus from contaminated environments or from virus particles in the air during milking or cleaning.
In the aftermath of the coronavirus pandemic, this study serves as a wake-up call. It shows that viruses can take unexpected paths as they evolve and spread. While there’s no immediate cause for alarm, it’s a reminder of why scientists work tirelessly to track and understand these microscopic invaders. Their work could help keep humanity one step ahead, ensuring we’re prepared for whatever nature might throw our way next.
The study received funding from the Animal Health Diagnostic Center in Cornell’s College of Veterinary Medicine, the Ohio Animal Disease and Diagnostic Laboratory, the Texas A&M Veterinary Medical Diagnostic Laboratory, and the USDA.
