Pathological changes of edwardsielliasis may be summarized as suppurative inflammation in eels, Anguilla japonica, and can be divided into two types, the type of suppurative hepatitis and the combined type of suppurative hepatitis and interstitial nephritis. In the early stage of the pathological changes, suppurative inflammation was observed in liver, and then scattered abscess, suppurative ulcer hyperaemia in other organs, such as kidney, spleen and stomach, and on body surface. Other pathological changes include the degeneration and necrosis of hepatocytes and epithelium cells of renal tubule, and hyperaemia and haemorrhage of blood vessels in liver and kidney. Pathological changes in ultrastructure of liver, kidney and spleen were also examined. Based on the pathological observations, edwardsielliasis may also be named as the suppurative liver-kidney :Inflammation or the suppurative liver-kidney disease.