PROPERTIES OF IRIDOVIRUSES FROM ORNAMENTAL FISH

An iridovirus from 2 species of freshwater tropical imported fish was examined for its antigenic and biochemical properties and virulence fo r 3 species of food fish. The virus was found in both guppy (Poecilia reticulata) and doctor fish (Labroides dimidatus). The virus replicate d in numerous fish cell lines including BF-2, CCO and EPC. Virus titer s reached 10(8) TCID50/ml in each cell line. The virions had similar s ize and morphology to those previously reported to cause systemic infe ctions among catfish in Europe and from redfin perch and rainbow trout in Australia. A comparison of the ornamental fish iridovirus with the se systemic agents indicated that all share common antigens detected b y indirect fluorescent antibody tests and Western blots. Additionally, polymerase chain reactions using primer sets developed for the red fi n perch virus, amplified a segment of genomic DNA from the ornamental fish isolate. An examination of the virulence of the ornamental fish i solate for 2 important food fish species, rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus), indicated the forme r species was susceptible although mortality was low. Dead fish had si gnificant lesions in the liver and kidney and had titers of virus grea ter than 10(8) TCID50/g. We speculate that these iridoviruses, first d etected in Australia in redfin perch, are all related strains in the R anavirus genus that may have reached these geographically distant site s by movements of ornamental fish.