A case of H5N2 flu was found in a flock of 39,000 turkeys in Stearns County, which is northwest of Minneapolis, according to a notice from USDA. State officials quarantined the infected farm, and birds there will be culled to prevent the spread of the disease.

Recent infections of avian flu in states stretching from Arkansas to Oregon have prompted overseas buyers to limit imports of U.S. poultry from companies such as Tyson Foods Inc, Pilgrim's Pride Corp and Sanderson Farms Inc.

The USDA is developing a vaccine to protect poultry from new strains of avian flu, including H5N2, but has no plans to distribute it yet.