The following is a press release from the Cascade City-County Health Department:. Great Falls, MT — In early April, Highly Pathogenic Avian Influenza (HPAI), commonly known as bird flu, was detected in a commercial poultry flock in Cascade County. The exposed animals were culled and safely disposed of. HPAI has since been confirmed in several additional birds. The affected birds were wild or feral geese, a duck, and a great horned owl, all located in or near to Great Falls.