A bird flu summit is slated for tomorrow in Des Moines with Ag Secretary Tom Vilsack, Governor Branstad, and businessmen and farmers connected to the poultry industries.  One of the topics sure to come up is use of the bird flu vaccine that has been tested 100 percent effective in chickens.  USDA’s Dr. David Swayne says China and Vietnam have used bird vaccines, though, and it hasn’t always been a benefit.