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Virus Expert Explains "Very High Likelihood" of Bird Flu Spreading to Humans

Person-to-person spread of avian flu could mean the start of a new pandemic.

After COVID, we're all a little more on edge when it comes to the possibility of a new pandemic. But what are the chances of that happening with bird flu? There is currently widespread transmission of H5 bird flu in wild birds that is causing outbreaks among U.S. poultry and dairy cows. The concern for many experts and the general public, however, is that the virus will make a more significant jump to people. With four reported humans cases in the country—all from close contact with infected animals—one virus expert is now speaking out about the "very high likelihood" of bird flu eventually spreading between humans.

RELATED: CDC Issues New Alert After Human Case of Bird Flu in the U.S.—These Are the Symptoms.

Currently, there has been no known person-to-person spread of avian flu, according to the Centers for Disease Control and Prevention (CDC). But more humans have become infected in recent months.

The first confirmed human case of H5 bird flu in the U.S. was reported back in April 2022. The case involved a Colorado worker who had direct exposure to poultry that was presumed to be infected with the H5N1 bird flu strain.

The next case didn't occur until nearly two years later, when a person who had been exposed to dairy cows in Texas that were believed to be infected tested positive for H5N1. Notably, that transmission was not from birds.

"This is thought to be the first instance of likely mammal to human spread of HPAI A(H5N1) virus," the CDC states on its website.

Since then, two more people have tested positive for the virus, according to a May 30 update from the agency. Both were Michigan dairy farm workers who had exposure to infected cows.

In a recent interview with Yahoo News, Jenna Guthmiller, PhD, who has been studying the virus for years at the Department of Immunology and Microbiology at The University of Colorado Anschutz Medical Campus, shared that she's worried avian influenza is becoming an increasing threat to both animals and humans.

"We are just seeing the tip of the iceberg," she told the news outlet. "The number of people who are at risk of being exposed to this is really very high."

Guthmiller said she believes the H5N1 virus has been "ramping up" since its spread to dairy cows, which "could result in the virus jumping back into other mammals and continuing to spread."

RELATED: Second Human Bird Flu Case Is the "Tip of the Iceberg," Pandemic Expert Says.

Just a few days ago, the U.S. Department of Agriculture (USDA) reported for the first time that several house mice in New Mexico had tested positive for the virus.

"As we see more mammals become infected I think the concern that this could adapt, and we become one of those incidental mammal hosts, increases," Guthmiller told Yahoo News. "I feel the outbreak is uncontrolled, and we just do not have a good grasp of the breadth of the outbreak—how many farms are affected, how many different areas, the number of cows, the number of other animals that are getting infected."

So far, all infections of the bird flu in humans are believed to be the result of the virus spreading from contact with animals carrying the disease. But Guthmiller said it would be "genuinely worrying" if someone without any exposure to animals tested positive for H5N1, which "would imply human-to-human transmission."

"I don't think it's going to be a singular event where a dairy farm worker gets exposed to milk, gets infected, and that's going to be the thing that sets off a pandemic," she clarified.

"The virus is going to jump from cows to another animal, then jump back into dairy cows again. It's really just trying to figure out how it can keep going and infect the most amount of things," Guthmiller continued. "And I think at some point, it has a very high likelihood of gaining that capacity to make humans one of those hosts. If we really do not get this under control, I see those odds increasing further."

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.

Kali Coleman
Kali Coleman is a Senior Editor at Best Life. Her primary focus is covering news, where she often keeps readers informed on the ongoing COVID-19 pandemic and up-to-date on the latest retail closures. Read more
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