Dairy cattle in Nevada have been found to be infected with a new type of bird flu, distinct from the one that has been spreading in US herds since the previous year.
The big picture: This detection suggests that different strains of the Type A H5N1 virus have crossed over from wild birds into cattle on at least two occasions, raising concerns about the potential for wider spread and the difficulty in controlling infections in animals and humans who are in close contact with them.
- The new variant, known as D11, was identified in milk samples collected as part of a surveillance program initiated in December. It is distinct from the B313 strain of the H5N1 virus that was confirmed in cattle in late 2023 and has since affected over 950 herds across 16 states.
- The D11 strain has been linked to the first documented US fatality from bird flu, as well as severe illness in Canada. A person in Louisiana died in January after developing severe respiratory symptoms following exposure to wild and backyard birds. Additionally, a teenage girl in British Columbia was hospitalized for months due to a virus traced back to poultry.
Zoom out: At least 67 individuals in the US have been infected with bird flu, with a higher prevalence among those who closely interact with dairy or cattle, according to the US Centers for Disease Control and Prevention.
