COMPARISON OF RHABDOVIRUSES ASSOCIATED WITH EPIZOOTIC ULCERATIVE SYNDROME (EUS) WITH RESPECT TO THEIR STRUCTURAL PROTEINS, CYTOPATHOLOGY AND SEROLOGY

Seven rhabdoviruses isolated from fish suffering from epizootic ulcera tive syndrome (EUS) were compared in terms of their morphology, cytopa thogenicity, antigenic relatedness and structural polypeptide composit ion. All strains exhibited a bullet-shaped morphology, but the T9204 i solate was found to be longer and more variable in length than the oth er strains. Sixteen fish cell lines investigated showed some variation in susceptibility to each isolate, but the cytopathic changes induced by T9204 in SSN-2, RSN, GCP, ONP, FHM, AS and MUL lines were signific antly different fmn the other isolates. Polyclonal antisera raised aga inst the BPV, 20E and SL11 strains neutralized six isolates (BPV, 02, 19, 20E, A4 and SL11), but not T9204. Conversely, anti-T9204 serum onl y neutralized homologous virus. Polyacrylamide gel electrophoresis dem onstrated that BPV. 02, 19, 20E, A4 and SL11 had virtually identical p rotein profiles, whereas T9204 differed both in the number of protein bands and in their migration pattern. Western blots of these gels iden tified the proteins specific to T9201 that reacted with aati-T9204 ser um. Therefore, the isolates represent two distinct species of fish rha bdoviruses, but as yet, no causal relationship with EUS, or any other disease condition, has been established.