Flocks of poultry in Dane, Jefferson and Walworth counties have been infected with highly pathogenic avian influenza, according to the Wisconsin Department of Agriculture, Trade and Consumer Protection. 

The virus has been circulating across North America since 2021, infecting both wild and domesticated birds. The birds on the affected properties will be killed to prevent the further spread of disease, and DATCP has established a 10 kilometer control area around the infected premises in which the movement of poultry is restricted. 

The infected birds in Dane County were in a backyard poultry flock while in Jefferson and Walworth counties the affected birds were in commercial flocks, according to DATCP. 

Officials and farmers in Wisconsin have been managing avian flu infections since spring 2022 when outbreaks across the state shut down poultry shows, exhibits and swap meets. Last year, a dairy herd was quarantined after an infection was discovered. 

DATCP said it is monitoring farm workers at the affected facilities for signs of infection and recommends biosecurity measures to protect flocks and herds near where the current infections were found.