Four new cases of highly pathogenic avian influenza (HPAI) were confirmed on May 10, 2022, according to the latest information from the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS). These cases bring to total number of commercial flocks affected by HPAI this year to 172.

One of the cases was detected in Muskegon County, Michigan and includes 35,100 commercial turkey meat birds. This marks the first commercial HPAI case detected in the state.

The remaining three cases were all detected Pennsylvania. Two of the cases were confirmed in Berks County, affecting 23,800 commercial duck breeders and 37,300 commercial duck meat birds. The third case was found in Lancaster County, affecting 72,300 commercial table egg layers.

HPAI in Pennsylvania

These are not the first commercial HPAI cases detected in either Berks County or Lancaster County, Pennsylvania this year. Two HPAI cases in Berks County were confirmed, affecting 29,600 commercial duck breeders and 74,300 commercial duck meat birds.


Additionally, APHIS has confirmed eight commercial cases in total in Lancaster County, with seven of those being confirmed in April 2022. These include the most recent case on May 10 affecting 133,400 birds, four egg layer operations affecting 3,757,500 birds, one broiler operation affecting 50,300 birds, one broiler breeder pullet operation affecting 18,100 birds and one duck meat operation affecting 19,300 birds.

This brings the total number of commercial birds affected in the state of Pennsylvania to 4,082,500.

To learn more about HPAI cases in commercial poultry flocks in the United States and Canada, see an interactive map on

Read our ongoing coverage of the global avian influenza outbreak.