A person who caught bird flu after exposure to infected dairy cows has died, the first known US death from the virus in 2026. The Yakima County Health District in Washington reported the death on Sunday 1 November, a day after reporting the patient's hospitalisation.

The patient, who had underlying health conditions the county did not specify, is the third person in the US to die from bird flu since February 2024. County health officials are monitoring the patient's contacts to make sure the infection was not passed on.

The Centers for Disease Control and Prevention (CDC) says there is no known person-to-person spread and the public risk is low. Most of the more than 70 US cases since 2024 have been mild, and health officials say all were 'dead-end' infections.

Why Experts Are Alarmed

Dr Jennifer Nuzzo, who directs the Pandemic Center at Brown University's School of Public Health, said bird flu at Washington dairies has coincided with early seasonal flu on the US Pacific Coast. She said H5N1 could swap genome pieces with seasonal flu viruses.

Such a change could help the virus infect humans more easily. 'That is the bad scenario,' she said, adding that a mix 'we don't want to have' is a growing worry.

She also said the patchwork state-by-state approach to monitoring human infections is concerning. 'I just think that our picture of H5N1 is the murkiest it's ever been,' she said.

Jenna Guthmiller, PhD, of the University of Colorado School of Medicine, has said the more animals the virus can infect, the more likely it is that humans could become one it replicates in efficiently. She called its jump into cows 'quite shocking to the field'.

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Cases Tied to Infected Cows

The county has identified three human cases this year, all since mid-October and all linked to infected cows. The first was a mild case in a dairy worker who tested positive for H5N1 on 15 October, the first human case reported in nearly a year.

The third case, like the first, involves mild symptoms, and the patient has not been hospitalised. State health officials reported all three cases to the CDC, but the agency has not included them on its bird flu dashboard.

Since 8 October, 33 dairy herds infected with H5N1 have been reported in Washington. The state is urging dairy workers to wear personal protective equipment and report any symptoms if they feel ill.

How Workers Are Monitored

Dr Dave Atteberry, public health officer for the Yakima health district, said milk testing by state and federal agriculture departments found the infected dairies in early October. Workers were then enrolled in a daily text-based check for cough, fever or red eyes.

Anyone who reports symptoms gets follow-up questions, and workers who test positive are given antivirals to ease symptoms and lower their viral load. He said this is done 'out of an abundance of caution', as person-to-person spread has not been seen.

What Research Shows

A small study of experimentally infected cows, published in Nature, found the virus spreads between cattle mainly through milk and milking procedures, not respiratory spread. Experts said the findings may be reassuring but vigilance is still needed.

Daniel Olson, MD, PhD, of the Colorado School of Public Health, has said H5N1 has been highly pathogenic in people, with about a 50% death rate across fewer than 1,000 documented cases over 30 years. He added that he would not drink unpasteurised milk.

The US Food and Drug Administration says pasteurisation inactivates H5N1 and the commercial milk supply is safe. The agency sampled 464 pasteurised dairy products, including milk, cheese, butter and ice cream, and none contained viable virus.

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