Pseudomonas anguilliseptica as a pathogen of salmonid fish in Finland

Abstract

The bacterium Pseudomonas angui1liseptica Wakabayashi & Egusa, originally described as a pathogen of eel in Japan, was isolated from diseased Atlantic salmon Salmo salar, sea trout Salmo trutta, rainbow trout Salmo gairdneri, and whitefish Coregonus sp. in Finland. Biochemical tests showed that the Finnish isolates are similar to the Japanese strains except for the Tween 80 reaction. Serologically, the Finnish strains of P. anguilliseptica are related to the Japanese isolates from ayu Plecoglossus altivelis. Gross signs in diseased salmonids were similar to those described for European eel, i.e. petechial haemorrhages in the skin, peritoneum, and liver. The effect of oxytetracycline therapy was disappointing in some of the outbreaks in salmonid fish. Apparently, alternative drugs will have to be employed to control the disease on salmonid farms.