Lately, bird flu, or H5N1, has been making headlines after the first human death from it in the US. This might feel like deja vu from the early days of COVID-19, but bird flu and COVID-19 are quite different. COVID-19 was quickly spreading person-to-person when it arrived in the US in 2020, but bird flu has been around for a while, mostly affecting animals. Scientists know more about H5N1 than they initially knew about SARS-CoV-2, and the US has been preparing for its threat.

H5N1 is a type of avian influenza that mostly affects birds. Some strains are low-pathogenic, causing mild infections, while others, like H5N1, are highly pathogenic, killing birds easily. Although bird flu viruses mostly infect birds, they can also spread to other animals, including humans. Human infections are rare and usually don't spread from person to person.

H5N1 isn't new; it's been tracked since the 1990s. Recently, it's been making waves by infecting a variety of mammals, including marine mammals. In the US, over 130 million birds and many dairy herds have been affected. Human cases are rare, but they're on the rise.

Scientists worry that H5N1 could become a pandemic if the virus mutates to spread easily among humans. This happens when a virus copies itself and makes mistakes, or when segments of its genetic material swap with other viruses. H5N1 is currently bad at infecting humans, attacking the eyes rather than the respiratory tract. But given enough time, it could change to become better at infecting humans.

People catch bird flu through contact with infected animals. Most cases are mild, and there's no evidence of person-to-person spread in the US. Dairy and poultry workers and backyard bird owners are most at risk. Symptoms include red, irritated eyes, fever, and respiratory issues. Two severe cases have been reported, including the first US death from bird flu.

Cooking meat thoroughly and pasteurizing milk can kill H5N1. Avoid drinking raw milk or eating undercooked meat to stay safe.

Bird Flu in the US: What You Need to Know

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