Amphibian and Piscine Iridoviruses Proposal for Nomenclature and Taxonomy Based on Molecular and Biological Properties

Abstract

We have compared a number of properties of the well-characterized iridovirus, frog virus 3, with two other iridoviruses from amphibia, bullfrog edema virus and Lucké triturus virus, and with a piscine iridovirus, goldfish virus (GFV), to provide information for developing taxonomic classification of these viruses and establishing their ecological niche. Purified virions had similar size and shape (icosahedral) for each virus, and the genomic DNAs of each virus were methylated by a virus-induced DNA methyltransferase. The three amphibian viruses replicated equally well in fish (FHM), hamster (BHK), and human (WI-38) cell monolayer with identical cytopathology, while GFV failed to replicate in these cell lines. However, GFV replicated albeit at a slow rate, in a goldfish cell line; there was no detectable replication by the amphibian viruses in these cells. The amphibian iridoviruses had virtually similar DNA sequences, while those of GFV were markedly different. Analyses of virus-induced polypeptides in infected cells corroborated the DNA analyses; the polypeptides of the amphibian viruses were similar and distinct from those of the fish virus. Nongenetic reactivation could only be accomplished between the three amphibian viruses but not with the piscine virus. Based on these data, we suggest taxonomic and nomenclature designations of amphibian and piscine iridoviruses.

An iridovirus-like agent isolated from the ornate burrowing frog Limnodynastes ornatus in northern Australia

“…The isolate is similar in size, biological characteristics and CPE to ranaviruses isolated in North America (Essani & Granoff 1989). The North American ranaviruses 1, 2 and 3 will not replicate above 33 "C (Granoff et al 1965, Clark et al 1969, Gravell & Granoff 1970, Essani & Granoff 1989. The replication of the isolate from Limnodynastes ornatus showed a similar temperature sensitivity.…”

“…AZC inhibition of replication of the isolate indicates that DNA methylation is an essential process (Goorha et al 1984). The isolate is similar in size, biological characteristics and CPE to ranaviruses isolated in North America (Essani & Granoff 1989). The North American ranaviruses 1, 2 and 3 will not replicate above 33 "C (Granoff et al 1965, Clark et al 1969, Gravell & Granoff 1970, Essani & Granoff 1989.…”

“…Replication did the presence of DNA, are consistent with an indovirus occur at 34 "C in some mammalian cell lines, but titres (Francki et al 1991). The genus Ranavirus of the Iridoviridae have methylated cytosine residues and AZC inhibits methylation (Essani & Granoff 1989). AZC inhibition of replication of the isolate indicates that DNA methylation is an essential process (Goorha et al 1984).…”

Pathology, Isolation, and Preliminary Molecular Characterization of a Novel Iridovirus From Tiger Salamanders in Saskatchewan

“…Digestion of DNA from RRV infected cells with HindIII and XbaI showed profiles (Fig. 10) distinct from FV3, LT1, and other known ranaviruses (Essani and Granoff, 1989;Mao et al, 1997). To strengthen the suggestion that RRV is an iridovirus, DNA from RRV infected cells was digested with HpaII or MspI.…”

A polymerase chain reaction (PCR) to detect epizootic haematopoietic necrosis virus and Bohle iridovirus

“…Recent studies have compared EHNV with iridoviruses from the sheatfish Silurus glanis, the catfish Ictalurus melas and FV3 (Hedrick et al 1992, Hengstberger et al 1993. These studies showed that EHNV, BIV and FV3 belonged to the genus Ranavirus as do the sheatfish and catfish viruses (Essani & Granoff 1989, Hedrick et al 1992, Hengstberger et al 1993.…”