U.K. confirms H5N1 bird flu case in poultry worker

A human case of H5N1 bird flu has been confirmed in the U.K., according to health officials. The case was detected in a poultry worker.

The UK Health Security Agency (UKHSA) confirmed the case of influenza A(H5N1) in a person from the West Midlands region. The individual contracted the infection on a farm after prolonged and close contact with a large number of infected birds.

The person is currently well and was admitted to a High Consequence Infectious Disease (HCID) unit, according to the UKHSA. It is unclear whether they have experienced any symptoms.

Birds at the farm were found to have H5N1 clade 2.3.4.4b with the DI.2 genotype. The UKHSA is tracing all individuals who may have been in contact with the confirmed case.

This is the first reported H5N1 case in the U.K. since July 2023, when poultry workers were found to be carrying the virus during surveillance testing.

According to data collected by BNO, this is the first human case involving the DI.2 genotype of clade 2.3.4.4b. In North America, most infections have been linked to the B3.13 and D1.1 genotypes, with D1.1 causing the first U.S. death and a severe case in Canada.

A newer clade of H5N1 bird flu—2.3.4.4b—has raised concerns due to its global spread and the increasing number of cases in mammals, including hundreds of outbreaks among dairy cows in the U.S. since 2024. There has also been a limited but growing number of human cases linked to contact with birds or cows.

LINK: A list of all human cases of H5N1 bird flu since 2021

The new clade has resulted in 88 human cases worldwide since 2022, with the U.S. reporting the majority (74 cases). The U.K. ranks second, with the new case bringing its total to six. The remaining cases have been reported in Spain, Canada, Chile, Ecuador, and China.