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.