MINNEAPOLIS (WCCO) — Minnesota turkey farmers are a little on edge these days as the state’s waterfowl start to fly south for the winter.

Ducks and other waterfowl are believed to be the primary source of avian influenza. They are carriers of the bug, but are somehow immune to it.

The bird flu wiped out five million turkeys in Minnesota last spring. Just as farmers are getting back on their feet, Minnesota Turkey Growers Association Executive Director Steve Olson says they are nonetheless preparing for another possible outbreak.

Wholesale turkey and egg prices are still high as farmers continue to recover from the spring outbreak. Scientists are working on a bird flu vaccine in the meantime, but it is not expected to be ready until after this fall.