Susceptibility of European catfish (Silurus gianis) to Edwardsiella ictaluri

Abstract

Summary European catfish (Silurus glanis) were tested for their susceptibility to the bacterium Edwardsiella ictaluri. The LD50 of E. ictaluri when injected into European catfish was 5.4 × 106 compared to 7.1 times; 104 for channel catfish (Ictalurus punctatus). E. ictaluri was isolated from dead and moribund European catfish and the bacterium was also detected in kidney smears by an indirect fluorescent antibody (FA) technique. The bacterium was not isolated or detected by FA from surviving fish 15 days after injection. No clinical signs of E. ictaluri infection were noted in European catfish, but these were prevalent in the channel catfish. These experiments indicate that under experimental conditions European catfish are not as susceptible to E. ictaluri as channel catfish.