A man in Washington has tested positive for H5N1, marking the first human case of bird flu in the US this year.

The patient, who works on a dairy farm, was reportedly infected after being exposed to two infected cows.

H5N1 has become endemic on US dairy farms after ‘spilling over’ from birds in 2024, and has since infected more than 1,000 herds across dozens of states.

The person is not seriously ill and is isolating at home, according to the Washington State Department of Health.

Scientists have long warned that if H5N1 mutates and gains the ability to spread person-to-person, it could trigger the next global pandemic – and each new infection gives the virus more opportunities to replicate and change.

Last week, a 50-year-old man in Taiwan was infected with a different strain of bird flu, H7N7, genetic analysis of which showed the virus had undergone adaptations to spread more effectively between mammals.

Of the more than 1,000 people who have contracted H5N1 since it was first detected in the late…