STUDY ON THE EDWARDSIELLIASIS OF THE EEL

The present paper describes the symptoms of Edwardsielliasis and the characters of its pathogenic bacteria which are epidemic in some eel farms in Fujian Province.There are two types of symptoms of the diseased eel: the kidney type which shows mainly the pathological change in the kidney, and the liver type which shows mainly the pathological change in the liver.The strains of pathogenic bacteria isolated from the liver and kidney of diseased eels had identical characters. They belong to the genus Edwardsiella. The artificial infection was made by using E86-205 and all the infected eels died. The symptom was similar to that of natural incidence. When infection dosage was 1.7×107 active bacteria for each eel, mortality occurred after eight days. Again, the strain E86-203 was isolated from the infected dead eels and its characters were the same as those of E86-205. Both strains belonged to Gram-negative bacteria, measuring 0.6—0.8×0.8—2.4μm. They were peritrichous, motive, and facultatively anaerobic. They may ferment glucose and produce hydrogen sulfide; they are oxydase negative, peroxide hydrogenase positive, lysine decarboxylase positive, and ornithine and arginine negative. They may quickly utilize cellobiose.The above characters are different from those of Edwardsiella tarda, E. hoshinae and E. ictaluri. So, E86-205 is considered as a new species, and is named Edwardsiella fujianensis sp. nov.