Oral live attenuated Salmonella vaccine vectors expressing recombinant foreign antigens have previously been shown to stimulate systemic, mucosal, humoral, and cell-mediated immune responses against Salmonella and foreign antigens; and attenuated strains of Salmonella have long been approved for use in both human and veterinary medicine.  A major benefit of using Salmonella as a live vector is providing mucosal routes of immunization, providing the possibility of greatly enhanced protection as compared to parenteral vaccination.  Salmonella vectors also have the potential advantage of being extremely inexpensive to amplify/manufacture and, as they do not have to be injected and can be administered by spray or drinking water, they are much more acceptable for widespread administration to commercial poultry.  Recent research using attenuated Salmonella vaccine vectors against a variety of pathogens, including avian influenza and the food borne pathogens Salmonella and Campylobacter,has shown encouraging results.