According to a note in Poultry Med. studies conducted in the Republic of South Africa have demonstrated that outbreaks of fowl typhoid caused by Salmonella Gallinarum are in all probably attributed to administration of the presumably attenuated vaccine.  Whole genome sequencing demonstrated commonality between vaccine and outbreak strains with no evidence of wild-type S. Gallinarum as a pathogen.  Similar observations have been made in Belgium lending support to the presumption of reversion to virulence.

Fowl typhoid is endemic in southern Africa and numerous other nations in Asia and the Americas.  To protect flocks poultry health professionals now administer live mutant Salmonella Enteritidis vaccine that has common antigenic components with Salmonella Gallinarum.