News that bird flu has been spreading between cows for months and that fragments of the virus are even showing up in milk on U.S. grocery store shelves have fueled new worries about the risk the virus poses to people. Among the questions: Is the virus, known as highly pathogenic avian influenza H5N1, adapting to better infect mammals? And can people get bird flu from drinking that milk?
Science News went to the experts to find answers to those questions. The short answer is that, thanks to milk pasteurization and the way bird flu viruses spread, the risk to people remains low. Here’s a deeper dive into what you should know.
raw milk and products made from it. “We know that raw milk [can contain] other infectious diseases and there have been outbreaks linked to raw milk consumption. So categorically I don’t recommend it.”
Some goats have also been infected with H5N1, so Davis suggests avoiding raw goat and sheep milk products, too.
Could people get infected with bird flu through eating or drinking?
Decades of evidence suggest that’s not likely, Osterholm says.“We have no evidence that humans have become infected from influenza A virus via ingestion.”
Some scavenger mammals have become infected with H5N1 from eating dead birds. But to get into cells, influenza viruses need to grab onto receptors, cell surface proteins studded with certain sugars. In humans, those sugars are different than the versions in scavengers. People carry the entry portals in their upper respiratory tract and the eyes. The one person in the United States who recently caught bird flu worked with cows at a farm in Texas and was diagnosed with conjunctivitis, an eye infection.
It might even be difficult for people to catch the bird flu from infected cows, Osterholm says. “If you look at the experience we’ve had in the past, even with all of the human contact that occurred with infected flocks [of] turkeys and chickens over the course of the past several years, we’ve just seen an absence of infection in humans.” Both the U.S. Centers for Disease Control and Prevention and World Health Organization have designated the virus as low risk for humans.
Traces of bird flu are showing up in cow milk. Here’s what to know
