General Information: Edwardsiella ictaluri is the causative agent of enteric septicemia in catfish (ESC), an economically significant disease of farm-raised catfish. The acute form of ESC causes bacterial septicemia (proliferation of bacteria in the blood) which rapidly leads to death. The chronic form of this disease causes a characteristic head lesion, and may also proceed to septicemia and death. Two plasmids, which are consistently present in Edwardsiella ictaluri isolates, have been sequenced. Both plasmids contain genes for the type III secretory system, which is involved in translocating pathogenicity proteins into the eukaryotic cell.