H5N1 flu spreads in US cattle, raising pandemic concerns

H5N1, the avian flu that has devastated bird populations globally, is now spreading through US cattle herds. The virus has infected three people in Washington state, one of whom has died, bringing the total number of US infections since 2022 to 75.

Scientists warn that cuts to federal agencies under the Trump administration have allowed the virus to spread unchecked, increasing the risk of a human outbreak. The more the virus circulates in animals, the greater the chance it may adapt to humans.

H5N1 reached the US in 2021 through wild birds from Europe. It initially infected farmed poultry and occasionally jumped to mammals like seals, dolphins, and bears. However, in late 2023, the virus began spreading rapidly among cattle in Texas, leading to infections in hundreds of herds across 12 states.

Cattle infected with H5N1 often show no symptoms, allowing the virus to spread across state lines as animals are moved for milking. This practice has been criticized for its biosecurity risks. Experts say the outbreak in cattle is now the main route by which the virus is reaching people.

At least 50 of the 75 human cases in the US are linked to cattle farming. While most cases linked to cattle have been mild, the recent death of a person infected with the cow variant, genotype B.13, is concerning. The individual had underlying health conditions, but the development still raises alarms among experts.

Scientists are particularly worried that H5N1 could combine with seasonal influenza to create a new strain capable of spreading between people. This process, known as reassortment, could lead to a new flu pandemic. H5N1 has also spread to mink farms in Utah, where officials have not mandated culling despite the risk of the virus adapting to humans.