(Pierre, SD) — South Dakota’s senators are leading the way in efforts to try and get a potential bird flu vaccine available for usage. Mike Rounds and John Thune co-signed a letter to Secretary of Agriculture Tom Vilsack and U.S. Trade Representative Katherine Tai last week. They want to get discussions going on new trade agreements that have to be updated before any use of a possible HPAI vaccine can be allowed. The USDA is currently testing vaccines to highly pathogenic bird flu that has affected more than five million birds in South Dakota and had more than a billion-dollar impact nationwide.