Molecular characterization of a ranavirus isolated from largemouth bass Micropterus salmoides

An iridovirus, isolated from largemouth bass Micropterus salmoides followin g a die-off among adult fish and provisionally designated largemouth bass V irus (LMBV), was characterized by analysis of viral protein synthesis in in fected cells, viral DNA restriction fragment length polymorphisms (RFLP), a nd sequence determination of the major capsid protein and viral DNA methylt ransferase genes. All 3 approaches yielded results consistent with the sugg estion that LMBV was a member of the genus Ranavirus. Moreover, LMBV was ne arly identical to 2 isolates from Southeast Asia which had been previously detected in imported ornamental fish. It remains to be determined whether i nfection of largemouth bass resulted from exposure to an imported virus, or whether the presence of similar viruses in southeast Asia and the southeas tern United States indicates that iridovirus species are not geographically limited as suggested earlier, but rather globally distributed.