First observations of carp erythrodermatitis caused by atypical Aeromonas salmonicida in israeli bred Cyprinus carpio

The majority of Israeli fish farms that breed goldfish of the species Caras sius auratus have dealt with goldfish ulcer disease since early 1980. Durin g the spring of 1997 the first case of carp erythrodermatitis was observed within the Israeli leather common carp population, Cyprinus carpio (line Do r 70 x Yugoslavia). The disease spread quickly throughout the central and n orthern regions of the country, with the number of affected farms reaching 37 by summer 1999. Coomassie-positive, slow-growing bacteria were cultured from the wounds of affected fish. The isolates were compared with a strain of atypical Aeromonas salmonicida cultured from Israeli goldfish. This was accomplished by phenotypic and biochemical criteria as well as PCR and SDS- PAGE. Most of the isolates demonstrated an outer membrane protein profile s een in the atypical strain as well as a major 50 kDa outer membrane protein comparable to virulent A-protein of A. salmonicida. The 1400 bp yap gene w as also cloned by PCR. Blood serum chemistry demonstrated an acute disease status.