Abstract
A filamentous bacterium isolated from salmonid fish with bacterial gill disease was reviewed.The disease fish were collected in Gunma, Japan and Oregon, U.S.A. All cultures were found to be uniform in their morphological and physiological characteristics. They showed neither gliding motility nor swarming growth on agar media, such as cytophaga agar. On the basis of the characteristics given in the 8th edition of Bergey's Manusl, the bacteria fit most closely into genus Flavobacterium, section I.
The presence of a common antigen showed a similarity between the Japanese and the Oregonstrains. However they were separated into two serological groups on the basis of agglutininadsorption tests.
All cultures appeared abundantly on the surface of the gills of juvenile rainbow trout within18-24hours after exposure to the bacterial su.spension in an aquarium. However mortality among exposed groups of fish varied widely in different experiments.
