COMPARISON OF EPIZOOTIC HEMATOPOIETIC NECROSIS AND BOHLE IRIDOVIRUSES, RECENTLY ISOLATED AUSTRALIAN IRIDOVIRUSES

Epizootic haematopoietic necrosis virus (EHNV) and Bohle virus (BIV) are piscine and amphibian iridoviruses respectively which have been isolated in Australia from redfin perch Perca fluviatilis L., cultured rainbow trout Oncorhynchus mykiss (Walbaum) and the ornate burrowing frog Limnodynastes ornatus (Gray). To determine whether the viruses were similar they were examined at the ultrastructural, protein, antigenic and genomic levels. EHNV was found to differ from BIV in cytopathic effect on host cells, size, site of virus release, molecular weights of proteins and restriction endonuclease digest profiles of the respective DNA's. On the other hand both iridoviruses were also found to infect a similar range of tissue culture cells, exhibit a similar sequence of ultrastuctural events and possess proteins of similar antigenic reactivity. DNA from EHNV and BIV cross hybridized to a high level. When the BIV polypeptides were compared to the published data for purified frog virus 3 (FV3) and with the appropriate restriction enzyme profiles, a similarity was noted between the 2 viruses. This implies that EHNV, which shares many structural and biochemical characteristics with BIV, is itself related to the Ranavirus genus of iridoviruses.