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The channel catfish (Ictalurus punctatus, Rafinesque) ovary (CCO) cell line is the standard cell line used for channel catfish diagnostics. Next-gen sequencing studies of a virus cultured in the CCO cells revealed mitochondrial sequences matching those of brown bullhead (Ameiurus nebulosus, Lesueur). Therefore, we systematically performed partial cytochrome oxidase 1 gene sequencing of several sources of the CCO cell line and all matched the brown bullhead and not the channel catfish.

Herein, we present the complete mitochondrial genome of the Jaguar Loach, Yasuhikotakia splendida. The sequence was determined from an aquarium specimen using a next-generation sequencing approach. The annotated Y. splendida mitogenome was 16,695 bp in length and contained 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding control region. The Y. splendida mitogenome displayed an A + T bias with an overall base composition of 32.0% A, 24.7% T, 27.6% C, and 15.7% G. Maximum Likelihood and Bayesian phylogenetic analyses, based on the aligned mitogenome sequences of 22 botiid loach species from each of the 8 genera and 3 outgroups, generated nearly identical trees that supported the Jaguar Loach as the sister species to the Skunk Loach, Y. morleti.

As part of an ongoing investigation of harbor seal (Phoca vitulina) mortalities within Puget Sound, Washington State, United States, between October 2007 and July 2008, 25 seal cases were submitted for histopathology and ancillary diagnostic testing, including additional attempted virus isolation. In vitro granular and refractile cytopathic effects (CPE) were consistently observed in Vero.DogSLAMtag cells inoculated with tissue homogenates from three seals. Transmission electron microscopy of infected Vero.DogSLAMtag cells revealed cytoplasmic clusters of icosahedral viral particles morphologically consistent with members of the family Reoviridae. The complete genome of a novel species within the genus Orthoreovirus, tentatively named phocid orthoreovirus 1 (PhRV1), was determined by next-generation sequencing and confirmed by rt-PCR in isolates from the three harbor seals. This is the first report of an orthoreovirus infection associated with dead stranded harbor seals. Aside from the CPE and ultrastructural findings, no consistent signalment, gross pathology, histopathology, or ancillary diagnostic findings were identified with PhRV1 infection. Further research is needed to determine the prevalence, tissue tropism, transmission, pathogenicity, zoonotic potential, and host range of orthoreoviruses in pinnipeds. This study demonstrates the value of thorough necropsy investigations and a multidisciplinary team approach to advance our understanding of marine mammal health.

Carcinus maenas is in the top 100 globally invasive species and harbours a wide diversity of pathogens, including viruses. We provide a detailed description for a novel bunyavirus (Carcinus maenas Portunibunyavirus 1) infecting C. maenas from its native range in the Faroe Islands. The virus genome is tripartite, including large (L) (6766 bp), medium (M) (3244 bp) and small (S) (1608 bp) negative sense, single-stranded RNA segments. Individual genomic segments are flanked by 4 bp regions of similarity (CCUG). The segments encode an RNA-dependent RNA-polymerase, glycoprotein, non-structural protein with a Zinc-Finger domain and a nucleoprotein. Most show highest identity to the ‘Wenling Crustacean Virus 9’ from an unidentified crustacean host. Phylogenomics of crustacean-infecting bunyaviruses place them across multiple bunyavirus families. We discuss the diversity of crustacean bunyaviruses and provide an overview of how these viruses may affect the health and survival of crustacean hosts, including those inhabiting niches outside of their native range.

BackgroundQuestions persist about patterns of initial dissemination of SARS-CoV-2 in the United States in early 2020.MethodsIn February and March, 2020, environmental surface swab samples were collected from the handle of the main entry door of a major university building in Florida, as part of a pilot surveillance project screening for influenza. Samples were taken at the end of regular classroom hours, between the dates of February 1-5 and February 19-March 4, 2020. ResultsInfluenza H1N1pdm09 was isolated from the door handle on four of the 19 days sampled. Both SARS-CoV-2 and influenza virus were detected in the sample collected on February 21, 2020. Based on sequence analysis, the Florida SARS-CoV-2 strain (designated UF-11) was identical to strains being identified in Washington state during the same time period, while the earliest similar sequences were sampled in China/Hubei between Dec 30th 2019 and Jan 5th 2020. The first human case of COVID-19 was not officially reported in Florida until March 1st. In an analysis of sequences from COVID-19 patients in this region of Florida, there was only limited evidence of subsequent dissemination of the UF-11 strain. Identical or highly similar strains, possibly related through a common transmission chain, were detected with increasing frequency in Washington state between end of February and beginning of March. ConclusionsOur data provide further documentation of the rapid early spread of SARS-CoV-2, and underscore the likelihood that closely related strains were cryptically circulating in multiple U.S. communities before the first “official” cases were recognized.

Over the last decade, a number of USA aquaculture facilities have experienced periodic mortality events of unknown aetiology in their clownfish (Amphiprion ocellaris). Clinical signs of affected individuals included lethargy, altered body coloration, reduced body condition, tachypnea, and abnormal positioning in the water column. Samples from outbreaks were processed for routine parasitological, bacteriological, and virological diagnostic testing, but no consistent parasitic or bacterial infections were observed. Histopathological evaluation revealed individual cell necrosis and mononuclear cell inflammation in the branchial cavity, pharynx, oesophagus and/or stomach of four examined clownfish, and large basophilic inclusions within the pharyngeal mucosal epithelium of one fish. Homogenates from pooled external and internal tissues from these outbreaks were inoculated onto striped snakehead (SSN-1) cells for virus isolation and cytopathic effects were observed, resulting in monolayer lysis in the initial inoculation and upon repassage. Transmission electron microscopy of infected SSN-1 cells revealed small round particles (mean diameter=20.0–21.7 nm) within the cytoplasm, consistent with the ultrastructure of a picornavirus. Full-genome sequencing of the purified virus revealed a novel picornavirus most closely related to the bluegill picornavirus and other members of the genus Limnipivirus. Additionally, pairwise protein alignments between the clownfish picornavirus (CFPV) and other known members of the genus Limnipivirus yielded results in accordance with the current International Committee on Taxonomy of Viruses criteria for members of the same genus. Thus, CFPV represents a proposed new limnipivirus species. Future experimental challenge studies are needed to determine the role of CFPV in disease.

Members of the Poxviridae family are large, double-stranded DNA viruses that replicate in the cytoplasm of their host cells. The subfamily Chordopoxvirinae contains viruses that infect a wide range of vertebrates including marine mammals within the Balaenidae, Delphinidae, Mustelidae, Odobenidae, Otariidae, Phocidae, and Phocoenidae families. Recently, a novel poxvirus was found in a northern sea otter pup (Enhydra lutris kenyoni) that stranded in Alaska in 2009. The phylogenetic relationships of marine mammal poxviruses are not well established because of the lack of complete genome sequences. The current study sequenced the entire sea otterpox virus Enhydra lutris kenyoni (SOPV-ELK) genome using an Illumina MiSeq sequencer. The SOPV-ELK genome is the smallest poxvirus genome known at 127,879 bp, is 68.7% A+T content, is predicted to encode 132 proteins, and has 2546 bp inverted terminal repeats at each end. Genetic and phylogenetic analyses based on the concatenated amino acid sequences of 7 chorodopoxvirus core genes revealed the SOPV-ELK is 52.5-74.1% divergent from other known chordopoxviruses and is most similar to pteropoxvirus from Australia (PTPV-Aus). SOPV-ELK represents a new chordopoxvirus species and may belong to a novel genus. SOPV-ELK encodes eight unique genes. While the function of six predicted genes remains unknown, two genes appear to function as novel immune-modulators. SOPV-ELK-003 appears to encode a novel interleukin-18 binding protein (IL-18 BP), based on limited sequence and structural similarity to other poxviral IL-18 BPs. SOPV-ELK-035 appears to encode a novel tumor necrosis factor receptor-like (TNFR) protein that may be associated with the depression of the host's antiviral response. Additionally, SOPV-ELK-036 encodes a tumor necrosis factor-like apoptosis-inducing ligand (TRAIL) protein that has previously only been found in PTPV-Aus. The SOPV-ELK genome is the first mustelid poxvirus and only the second poxvirus from a marine mammal to be fully sequenced. Sequencing of the SOPV-ELK genome is an important step in unraveling the position of marine mammal poxviruses within the larger Poxviridae phylogenetic tree and provides the necessary sequence to develop molecular tools for future diagnostics and epidemiological studies.

We report the detection and gene coding sequences of three novel Orbivirus species found in six dead farmed white-tailed deer in the United States. Phylogenetic analyses indicate that the new orbiviruses are genetically closely related to the Guangxi, Mobuck, Peruvian horse sickness, and Yunnan orbiviruses, which are thought to be solely borne by mosquitos. However, four of the six viruses analyzed in this work were found as co-infecting agents along with a known cervid pathogen, epizootic hemorrhagic disease virus-2 (EHDV-2), raising questions as to whether the new viruses are primary pathogens or secondary pathogens that exacerbate EHDV-2 infections. Moreover, EHDV-2 is known to be a Culicoides-borne virus, raising additional questions as to whether Culicoides species can also serve as vectors for the novel orbiviruses, if mosquitoes can vector EHDV-2, or whether the deer were infected through separate bites by the insects. Our findings expand knowledge of the possible viral pathogens of deer in the United States. Moreover, due to the close genetic relatedness of the three new orbiviruses to viruses that are primary pathogens of cattle and horses, our findings also underscore a crucial need for additional research on the potential role of the three new orbiviruses as pathogens of other animals.

Although infections caused by megalocytiviruses have been reported from a wide range of finfish species for several decades, molecular characterisation of the viruses involved has been undertaken only on more recent cases. Sequence analysis of the major capsid protein and adenosine triphosphatase genes is reported here from formalin-fixed, paraffin-embedded material from 2 archival ornamental fish cases from 1986 and 1988 in conjunction with data for a range of genes from fresh frozen tissues from 5 cases obtained from 1991 through to 2010. Turbot reddish body iridovirus (TRBIV) genotype megalocytiviruses, previously not documented in ornamental fish, were detected in samples from 1986, 1988 and 1991. In contrast, megalocytiviruses from 1996 onwards, including those characterised from 2002, 2006 and 2010 in this study, were almost indistinguishable from infectious spleen and kidney necrosis virus (ISKNV). Three of the species infected with TRBIV-like megalocytiviruses from 1986 to 1991, viz. dwarf gourami Trichogaster lalius (formerly Colisa lalia), freshwater angelfish Pterophyllum scalare and oscar Astronotus ocellatus, were infected with ISKNV genotype megalocytiviruses from 2002 to 2010. The detection of a TRBIV genotype isolate in ornamental fish from 1986 represents the index case, confirmed by molecular sequence data, for the genus Megalocytivirus.

A novel virus from moribund European chub (Squalius cephalus) was isolated on epithelioma papulosum cyprini (EPC) cells. Transmission electron microscopic examination revealed abundant non-enveloped, hexagonal virus particles in the cytoplasm of infected EPC cells consistent with an iridovirus. Illumina MiSeq sequence data enabled the assembly and annotation of the full genome (128,216 bp encoding 108 open reading frames) of the suspected iridovirus. Maximum Likelihood phylogenetic analyses based on 25 iridovirus core genes supported the European chub iridovirus (ECIV) as being the sister species to the recently-discovered scale drop disease virus (SDDV), which together form the most basal megalocytivirus clade. Genetic analyses of the ECIV major capsid protein and ATPase genes revealed the greatest nucleotide identity to members of the genus Megalocytivirus including SDDV. These data support ECIV as a novel member within the genus Megalocytivirus. Experimental challenge studies are needed to fulfill River&rsquo, s postulates and determine whether ECIV induces the pathognomonic microscopic lesions (i.e., megalocytes with basophilic cytoplasmic inclusions) observed in megalocytivirus infections.

Here, we report the complete coding sequences of tilapia lake virus (TiLV) associated with syncytial hepatitis of tilapia (SHT). The TiLV strain was sequenced from the liver RNA extract of a moribund Nile tilapia (Oreochromis niloticus) fingerling from an Ecuadorian aquaculture facility in 2012.

Mariculture of Florida pompano Trachinotus carolinus in Central America has increased over the last few decades and it is now a highly valued food fish. High feed costs and infectious diseases are significant impediments to the expansion of mariculture. Members of the genus Megalocytivirus (MCV), subfamily Alphairidovirinae, within the family Iridoviridae, are emerging pathogens that negatively impact Asian mariculture. A significant mortality event in Florida pompano fingerlings cultured in Central America occurred in October 2014. Affected fish presented with abdominal distension, darkening of the skin, and periocular hemorrhages. Microscopic lesions included cytomegalic 'inclusion body-bearing cells' characterized by basophilic granular cytoplasmic inclusions in multiple organs. Transmission electron microscopy revealed arrays of hexagonal virions (155-180 nm in diameter) with electron-dense cores within the cytoplasm of cytomegalic cells. Pathological findings were suggestive of an MCV infection, and the diagnosis was later confirmed by partial PCR amplification and sequencing of the viral gene encoding the myristylated membrane protein. The viral sequence revealed that the fingerlings were infected with an MCV genotype, red seabream iridovirus (RSIV), previously reported only from epizootics in Asian mariculture. This case underscores the threat RSIV poses to global mariculture, including the production of Florida pompano in Central America.

The genus Megalocytivirus is the most recently described member of the family Iridoviridae; as such, little is known about the genetic diversity of this genus of globally emerging viral fish pathogens. We sequenced the genomes of 2 megalocytiviruses (MCVs) isolated from epizootics involving South American cichlids (oscar Astronotus ocellatus and keyhole cichlid Cleithracara maronii) and three spot gourami Trichopodus trichopterus sourced through the ornamental fish trade during the early 1990s. Phylogenomic analyses revealed the South American cichlid iridovirus (SACIV) and three spot gourami iridovirus (TSGIV) possess 116 open reading frames each, and form a novel clade within the turbot reddish body iridovirus genotype (TRBIV Clade 2). Both genomes displayed a unique truncated paralog of the major capsid protein gene located immediately upstream of the full-length parent gene. Histopathological examination of archived oscar tissue sections that were PCR-positive for SACIV revealed numerous cytomegalic cells characterized by basophilic intracytoplasmic inclusions within various organs, particularly the anterior kidney, spleen, intestinal lamina propria and submucosa. TSGIV-infected grunt fin (GF) cells grown in vitro displayed cytopathic effects (e.g. cytomegaly, rounding, and refractility) as early as 96 h post-infection. Ultrastructural examination of infected GF cells revealed unenveloped viral particles possessing hexagonal nucleocapsids (120 to 144 nm in diameter) and electron-dense cores within the cytoplasm, consistent with the ultrastructural morphology of a MCV. Sequencing of SACIV and TSGIV provides the first complete TRBIV Clade 2 genome sequences and expands the known host and geographic range of the TRBIV genotype to include freshwater ornamental fishes traded in North America.

Since its discovery in 2014, tilapia lake virus (TiLV) has emerged as a significant cause of mortality in tilapia cultured in Asia, Africa, and South America. Here, we report the complete genome sequence of a TiLV isolate obtained during a diagnostic investigation of an ongoing mortality event involving Nile tilapia cultured in Thailand.

The 149,343-bp genome of silurid herpesvirus 1, which was isolated in Thailand from glass catfish, was sequenced. The genome was most closely related to that of ictalurid herpesvirus 2, which infects black bullhead catfish. To our knowledge, this was the first silurid catfish alloherpesvirus genome to be sequenced.

The genome sequence of a papillomavirus was determined from fecal samples collected from bottlenose dolphins in the Indian River Lagoon, FL. The genome was 7,772 bp and displayed a typical papillomavirus genome organization. Phylogenetic analysis supported the bottlenose dolphin papillomavirus as being a novel type of Omikronpapillomavirus 1 .

Here, we report the complete genome sequence of Epizootic hemorrhagic disease virus (EHDV) serotype 6 (EHDV-6), isolated from a Florida white-tailed deer ( Odocoileus virginianus ) in 2016. To our knowledge, this is the first full genome sequence determined for an EHDV-6 isolate from Florida.

The order Herpesvirales includes viruses that infect aquatic and terrestrial vertebrates and several aquatic invertebrates (i.e. mollusks), and share the commonality of possessing a double-stranded DNA core surrounded by an icosahedral capsid. Herpesviruses of the family Alloherpesviridae that infect fish and amphibians, including channel catfish virus and koi herpes - virus, negatively impact aquaculture. Here, we describe a novel herpesvirus infection of wild European perch from lakes in Finland. Infected fish exhibited white nodules on the skin and fins, typically in the spring when prevalence reached nearly 40% in one of the sampled lakes. Transmission electron microscopic examination of affected tissues revealed abundant nuclear and cytoplasmic virus particles displaying herpesvirus morphology. Degenerate PCR targeting a conserved region of the DNA polymerase gene of large DNA viruses amplified a 520 bp product in 5 of 5 affected perch skin samples tested. Phylogenetic analysis of concatenated partial DNA polymerase and terminase (exon 2) gene sequences produced a well-supported tree grouping the European perch herpesvirus with alloherpesviruses infecting acipenserid, esocid, ictalurid, and salmonid fishes. The phenetic analysis of the European perch herpesvirus partial DNA polymerase and terminase nucleotide gene sequences ranged from 34.6 to 63.9% and 39.6 to 59.6% to other alloherpesviruses, respectively. These data support the European perch herpesvirus as a new alloherpesvirus, and we propose the formal species designation of Percid herpesvirus 2 (PeHV2) to be considered for approval by the International Committee on Taxonomy of Viruses. peerReviewed

Human coronavirus strain 229E (HCoV-229E) and human alphaherpesvirus 1 were isolated from the plasma of a Haitian child in 2016 with suspected arbovirus diseases. To our knowledge, this is the first description of HCoV-229E in human plasma, which is the focus of this article.

Epizootic hemorrhagic disease virus (EHDV) serotypes 1 and 2 were isolated from Florida white-tailed deer in 2015 and 2016, respectively, and their genomes were completely sequenced. To our knowledge, these are the first full genome sequences for EHDV-1 and -2 from Florida.

Beluga whale alphaherpesvirus 1 was isolated from a blowhole swab taken from a juvenile beluga whale. The genome is 144,144 bp in size and contains 86 putative genes. The virus groups phylogenetically with members of the genus Varicellovirus in subfamily Alphaherpesvirinae and is the first alphaherpesvirus sequenced from a marine mammal.

A herpesvirus genome was sequenced directly from a biopsy specimen of a rectal lesion from a female common bottlenose dolphin. This genome sequence comprises a unique region (161,235 bp) flanked by multiple copies of a terminal repeat (4,431 bp) and contains 72 putative genes. The virus was named common bottlenose dolphin gammaherpesvirus 1.

Ranaviruses are emerging pathogens of fish, amphibians, and reptiles that threaten aquatic animal industries and wildlife worldwide. Our objective was to genetically characterize ranaviruses isolated during separate bullfrog Lithobates catesbeianus die-offs that occurred eight years apart on the same North American farm. The earlier outbreak was due to a highly pathogenic strain of common midwife toad virus (CMTV) previously known only from Europe and China. The later outbreak was due to a chimeric ranavirus that displayed a novel genome arrangement and a DNA backbone typical for Frog virus 3 (FV3) strains except for interspersed fragments acquired through recombination with the CMTV isolated earlier. Both bullfrog ranaviruses are more pathogenic than wild-type FV3 suggesting recombination may have resulted in the increased pathogenicity observed in the ranavirus isolated in the later outbreak. Our study underscores the role international trade in farmed bullfrogs may have played in the global dissemination of highly pathogenic ranaviruses.

During regulatory sampling of fathead minnows (Pimephales promelas), a novel calicivirus was isolated from homogenates of kidney and spleen inoculated into bluegill fry (BF-2) cells. Infected cell cultures exhibiting cytopathic effects were screened by PCR-based methods for selected fish viral pathogens. Illumina HiSeq next generation sequencing of the total RNA revealed a novel calicivirus genome that showed limited protein sequence similarity to known homologs in a BLASTp search. The complete genome of this fathead minnow calicivirus (FHMCV) is 6564 nt long, encoding a polyprotein of 2114 aa in length. The complete polyprotein shared only 21% identity with Atlantic salmon calicivirus,followed by 11% to 14% identity with mammalian caliciviruses. A molecular detection assay (RT-PCR) was designed from this sequence for screening of field samples for FHMCV in the future. This virus likely represents a prototype species of a novel genus in the family Caliciviridae, tentatively named “Minovirus”.

Members of the family Iridoviridae, collectively referred to as iridovirids, are large, double-stranded DNA-containing viruses that infect invertebrates and cold-blooded (ectothermic) vertebrates. Infections in the former often lead to massive levels of virus replication resulting in iridescence of the infected animal and ultimately death. Among the latter, infections target a variety of organs and are capable of causing high levels of morbidity and mortality among commercially and ecologically important fish and amphibian species. The viral replication strategy has been elucidated primarily through the study of frog virus 3 (FV3) with additional input from other iridovirids of ecological or commercial importance. Replication occurs within both nuclear and cytoplasmic compartments and involves synthesis of genome length and concatemeric DNA, extensive methylation of the viral genome (among vertebrate viruses only), coordinate expression of three classes of viral gene products, and formation of icosahedral virions within cytoplasmic viral assembly sites. Phylogenetic analyses delineate five genera within the family and suggest that members of the families Iridoviridae, Ascoviridae, and Marseilleviridae compromise a monophyletic lineage in which ascoviruses are most closely related to invertebrate iridoviruses.

Ranaviruses were isolated from wild edible frogs ( Pelophylax esculentus ) during epizootics in Denmark and Italy. Phylogenomic analyses revealed that these isolates are closely related and belong to a clade of ranaviruses that includes the Andrias davidianus ranavirus (ADRV), common midwife toad ranavirus (CMTV), Testudo hermanni ranavirus (THRV), and pike-perch iridovirus (PPIV).

Blue spot disease, believed to be caused by esocid herpesvirus 1 (EsHV1), has been observed in wild northern pike Esox lucius in a number of cold-water locations, including the northern USA, Canada, and Ireland. In the spring of 2014, a northern pike was caught in Wisconsin displaying the characteristic bluish-white circular plaques on the dorsum and fins. Microscopic examination of hematoxylin and eosin-stained sections of the proliferative cutaneous lesions revealed a focally extensive abundance of panepidermal, megalocytic keratinocytes with karyomegaly. Enlarged nuclei stained basophilic, and an abundance of coarse eosinophilic granules were observed in the expanded cytoplasm. Transmission electron microscopy revealed aggregates of enveloped virus particles with electron-dense, hexagonal nucleocapsids surrounded by a uniformly staining ellipsoidal tegument layer within cytoplasmic vacuoles of megalocytic epidermal cells. More than 7000 bp of the EsHV1 genome were sequenced from infected skin tissues. Phylogenetic and phenetic analyses, based on the partial DNA-dependent DNA polymerase and terminase gene sequences, revealed EsHV1 forms a novel branch within the family Alloherpesviridae as the sister group to the clade that includes members of the genera Ictalurivirus and Salmonivirus. The gross, microscopic, and ultrastructural lesions reported in our study were identical to previous reports of blue spot disease in northern pike; however, here we provide the first molecular evidence supporting EsHV1 as a new species in the family Alloherpesviridae.

Bohle iridovirus (BIV) is a species within the genus Ranavirus , family Iridoviridae , first isolated from the ornate burrowing frog Limnodynastes ornatus in Australia. The BIV genome confirms it is closely related to isolates from boreal toad Anaxyrus boreas and leaf-tailed gecko Uroplatus fimbriatus within the United States and Germany, respectively.

Megalocytiviruses, such as infectious spleen and kidney necrosis virus (ISKNV), induce lethal systemic diseases in both ornamental and food fish species. In this study, we investigated an epizootic affecting Nile tilapia Oreochromis niloticus cultured in the US Midwest. Diseased fish displayed lethargy, gill pallor, and distension of the coelomic cavity due to ascites. Histopathological examination revealed a severe systemic abundance of intravascular megalocytes that were especially prominent in the gills, kidney, spleen, liver, and intestinal submucosa. Transmission electron microscopic examination revealed abundant intracytoplasmic polygonal virions consistent with iridovirus infection. Comparison of the full-length major capsid protein nucleotide sequences from a recent outbreak with a remarkably similar case that occurred at the same facility many years earlier revealed that both epizootics were caused by ISKNV. A comparison of this case with previous reports suggests that ISKNV may represent a greater threat to tilapia aquaculture than previously realized.

The pike-perch iridovirus (PPIV) was isolated in Finland from apparently healthy pike-perch fingerlings during routine disease surveillance. Our phylogenomic analysis revealed that PPIV is the first fish member of a clade of ranaviruses previously described from European and Chinese amphibians.

The Iridoviridae is a family of large, icosahedral viruses with double-stranded DNA genomes ranging in size from 103 to 220 kbp. Members of the subfamily Alphairidovirinae infect ectothermic vertebrates (bony fish, amphibians and reptiles), whereas members of the subfamily Betairidovirinae mainly infect insects and crustaceans. Infections can be either covert or patent, and in vertebrates they can lead to high levels of mortality among commercially and ecologically important fish and amphibians. This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Iridoviridae, which is available at www.ictv.global/report/iridoviridae.

Ranaviruses have been isolated from Atlantic cod ( Gadus morhua ) and turbot ( Scophthalmus maximus ) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the ranavirus tree branching off near other fish ranaviruses.

The short-finned eel ranavirus (SERV) was isolated from short-finned eel imported to Italy from New Zealand. Phylogenomic analyses revealed that SERV is a unique member of the genus Ranavirus , family Iridoviridae , branching at the base of the tree near other fish ranaviruses.