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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.

Here, we present the complete coding sequences of two tilapia lake virus (TiLV) isolates recovered during an investigation of a mortality event in farmed Nile tilapia in the United States. Phylogenetic analysis supported the isolates as each other’s closest relatives and members of a clade of Thai TiLV strains.

Here, we present the complete coding sequences of two tilapia lake virus (TiLV) isolates recovered during an investigation of a mortality event in farmed Nile tilapia in the United States. Phylogenetic analysis supported the isolates as each other’s closest relatives and members of a clade of Thai TiLV strains.

A lethargic juvenile male harp seal (

The commercial production of lumpfish

Recent genomic and metagenomic studies have led to a dramatic expansion of the known diversity of nucleocytoplasmic large DNA viruses (NCLDVs) of eukaryotes, which include giant viruses of protists and important pathogens of vertebrates, such as poxviruses. However, the characterization of viruses from nonmodel hosts still lags behind. We sequenced the complete genomes of three viruses infecting crustaceans, the Caribbean spiny lobster, demon shrimp, and European shore crab. These viruses have the smallest genomes among the known NCLDVs, with losses of many core genes, some of which are shared with iridoviruses. The deterioration of the transcription apparatus is compatible with microscopic and ultrastructural observations indicating that these viruses replicate in the nucleus of infected cells rather than in the cytoplasm. Phylogenomic analysis indicates that these viruses are sufficiently distinct from all other NCLDVs to justify the creation of a separate family, for which we propose the name “Mininucleoviridae” (i.e., small viruses reproducing in the cell nucleus)., Panulirus argus virus 1 (PaV1) is the only known virus infecting the Caribbean spiny lobster (Panulirus argus) from the Caribbean Sea. Recently, related viruses, Dikerogammarus haemobaphes virus 1 (DhV1) and Carcinus maenas virus 1 (CmV1), have been detected in the demon shrimp (Dikerogammarus haemobaphes) and the European shore crab (Carcinus maenas), respectively, from sites in the United Kingdom. The virion morphology of these crustacean viruses is similar to that of iridoviruses. However, unlike iridoviruses and other nucleocytoplasmic large DNA viruses (NCLDVs), these viruses complete their morphogenesis in the host cell nucleus rather than in the cytoplasm. To date, these crustacean viruses have remained unclassified due to a lack of genomic data. Using an Illumina MiSeq sequencer, we sequenced the complete genomes of PaV1, CmV1, and DhV1. Comparative genome analysis shows that these crustacean virus genomes encode the 10 hallmark proteins previously described for the NCLDVs of eukaryotes, strongly suggesting that they are members of this group. With a size range of 70 to 74 kb, these are the smallest NCLDV genomes identified to date. Extensive gene loss, divergence of gene sequences, and the accumulation of low-complexity sequences reflect the extreme degradation of the genomes of these “minimal” NCLDVs rather than any direct relationship with the NCLDV ancestor. Phylogenomic analysis supports the classification of these crustacean viruses as a distinct family, “Mininucleoviridae,” within the pitho-irido-Marseille branch of the NCLDVs.

Infections caused by mule deerpox virus (MDPV) have been sporadically reported in North American cervids. White-tailed deer (Odocoileus virginianus) fawns from a farm located in South Central Florida presented with ulcerative and crusting lesions on the coronary band as well as the mucocutaneous tissues of the head. Evaluation of the crusted skin lesions was undertaken using microscopic pathology and molecular techniques. A crusted skin sample was processed for virus isolation in four mammalian cell lines. The resulting isolate was characterized by negative staining electron microscopy and deep sequencing. Histopathologic evaluation of the skin lesions from the fawns revealed a hyperplastic and proliferative epidermis with ballooning degeneration of epidermal and follicular keratinocytes with intracytoplasmic eosinophilic inclusions. Electron microscopy of cell culture supernatant demonstrated numerous large brick-shaped particles typical of most poxviruses. Polymerase chain reaction assays followed by Sanger sequencing revealed a poxvirus gene sequence nearly identical to that of previous strains of MDPV. The full genome was recovered by deep sequencing and genetic analyses supported the Florida white-tailed deer isolate (MDPV-F) as a strain of MDPV. Herein, we report the first genome sequence of MDPV from a farmed white-tailed deer fawn in the South Central Florida, expanding the number of locations and geographic range in which MDPV has been identified.

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.

Cetaceanpox viruses (CePVs) are associated with a cutaneous disease in cetaceans often referred to as "tattoo" lesions. To date, only partial genomic data are available for CePVs, and thus, they remain unclassified members of the subfamily Chordopoxvirinae within the family Poxviridae. Herein, we describe the first complete CePV genome sequenced from the tattoo lesion of a managed Indo-Pacific bottlenose dolphin (Tursiops aduncus), using next-generation sequencing. The T. aduncus CePV genome (CePV-TA) was determined to encode 120 proteins, including eight genes unique to the CePV-TA and five genes predicted to function as immune-evasion genes. The results of CePV-TA genetic analyses supported the creation of a new chordopoxvirus genus for CePVs. The complete sequencing of a CePV represents an important first step in unraveling the evolutionary relationship and taxonomy of CePVs, and significantly increases our understanding of the genomic characteristics of these chordopoxviruses.

Tissues from a juvenile Longman's beaked whale that stranded in Hawaii in 2010 were screened for viruses using a Next-Generation Sequencing (NGS) approach. From the NGS data, the full genome (1,849 bp) of a novel beaked whale circovirus (BWCV) was determined. Two open reading frames (ORF) were annotated, including ORF1 that encodes the capsid gene, ORF2 that encodes the replication-associated gene, and a 9-bp conserved nonamer on the apex of the open loop found in all circoviruses. Independent phylogenetic analyses based on amino acid sequence alignments of the two CV proteins supported the BWCV as a member of the genus Circovirus, branching as the sister species to the recently discovered canine circovirus. A sequence identity matrix generated from complete genome alignments revealed the BWCV displays between from 51.1 to 56.7% nucleotide identity to other circoviruses, which is lower than the 80% threshold proposed for species demarcation. Considering the genetic and phylogenetic analyses, we propose the formal species designation of beaked whale circovirus. An endpoint PCR assay targeting the BWCV genome confirmed the presence of the BWCV DNA in every tissue from which DNA was extracted, including spleen, muscle, left ventricle, left adrenal gland, liver, lung, cerebrum, cerebellum, and lymph node. An automated in situ hybridization assay utilizing RNAscope® technology and targeting the replication-associated gene resulted in labeling of individual cells morphologically resembling mononuclear leukocytes and cells of blood vessels in diaphragm, liver, lymph nodes, lung, pericardium, oral mucosa and tongue, adrenal gland, testis, aorta, intestine, stomach and heart. The clinical or pathologic significance of BWCV is undetermined, as are its host range, prevalence, and pathogenicity in cetaceans of Hawaiian waters and elsewhere.

An adult male harbour porpoise (Phocoena phocoena) stranded off the coast of Alaska displaying poor body condition, scattered mild ulcerative dermatitis, and necrotizing balanoposthitis. Necropsy findings included severe verminous panniculitis, pneumonia, hepatitis, and enteritis. Histopathological examination of skin lesions revealed a pustular epidermitis and dermatitis, with ballooning degeneration of keratinocytes and occasional amphophilic intracytoplasmic inclusion bodies. A swab sample collected from the ulcerative penile lesions was processed for virus isolation resulting in cytopathic effects observed in primary beluga whale kidney (BWK) cells. Transmission electron microscopy revealed bullet-shaped virions budding from the cell surface of infected BWK cells consistent with a rhabdovirus. A cDNA library was prepared using RNA extracted from infected cell culture supernatant and sequenced on an Illumina MiSeq sequencer. The near-complete genome of a novel rhabdovirus was recovered. Genetic and phylogenetic analyses based on the complete L gene supported the harbour porpoise rhabdovirus (HPRV) as a new species. HPRV clustered phylogenetically with dolphin rhabdovirus (DRV) and this cetacean rhabdovirus clade was found to be the sister group to members of the genus Perhabdovirus that infect fish. A specific nested RT-PCR assay detected HPRV RNA in the epaxial musculature of the harbour porpoise. Our results are consistent with a previous hypothesis that cetacean rhabdoviruses may have arisen following a host jump from fish and suggest that DRV and HPRV represent separate species belonging in a new genus within the family Rhabdoviridae. Further research is needed to determine the health impact of HPRV in harbour porpoise populations, its prevalence, and route of transmission.

We report the complete genome sequencing of the first fish peribunyavirus determined using a next-generation sequencing approach. The virus was isolated during a routine health assessment of wild largemouth bass (Micropterus salmoides) in Wisconsin in April of 2009. Further research is needed to determine the epidemiology and pathogenicity of the largemouth bass bunyavirus.

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.

Tilapia lake virus is a globally emerging virus responsible for episodes of mass mortality in cultured and/or feral tilapia (Oreochromis spp. and hybrids) in Asia, Africa, Central America, and South America. Since 2014, there have been global reports of TiLV disease resulting in 10% to 90% mortality in tilapia fry, juveniles, and adults causing significant economic losses. Currently, the disease has been confirmed in Colombia, Ecuador, Egypt, India, Indonesia, Israel, Malaysia, Mexico, Philippines, Peru, Tanzania, and Thailand. TiLV has not yet been found in the USA or Canada, but it has most recently been reported in 20 aquaculture production facilities across six Mexican states (Chiapas, Jalisco, Michoacán, Sinaloa, Tabasco and Veracruz). This 7-page fact sheet written by Lowia Al-Hussinee, Kuttichantran Subramaniam, Win Surachetpong, Vsevolod Popov, Kathleen Hartman, Katharine Starzel, Roy Yanong, Craig Watson, Hugh Ferguson, Salvatore Frasca Jr., and Thomas Waltzek and published by the UF/IFAS School of Forest Resources and Conservation, Program in Fisheries and Aquatic Sciences describes this important emerging disease and explains how to prevent outbreaks and what to do if you suspect TiLV in an aquaculture facility or in the wild. http://edis.ifas.ufl.edu/fa213

A group of five juvenile Meller's chameleons (

The fish practitioner may encounter a new fish owner who brings their pet to the veterinary office as a beloved member of the family or a client with an ornamental backyard fishpond. As compared to land-dwelling animals, fish patients have the added challenge that their water environment plays a critical role in their health. An assessment of the patient's neurological status should be performed prior to induction of anesthesia. The mouth of each patient should be opened and examined with a light source. Good sample selection, especially in population health–type evaluations where disease prevalence can be low, is critical. Fish may also exhibit other characteristic signs of disease. The general history should focus on determining what species are affected, what clinical signs have been appreciated by the client and the time course of the disease. Numerous factors will guide the clinician's approach to disease diagnostics for each case.

The complete genome sequence of an alloherpesvirus isolated from blue catfish (Ictalurus furcatus) is reported. Genomic analyses revealed that this virus is a distinct strain of ictalurid herpesvirus 1, the first strain of which was isolated previously from a channel catfish (Ictalurus punctatus).

Here, we report the coding sequences of Big Cypress orbivirus isolated from a dead white-tailed deer (Odocoileus virginianus) from Florida in 2017. To our knowledge, this is the first detection of Big Cypress orbivirus in a vertebrate host.

Genomic sequence analysis of zoo ranavirus (ZRV) suggests it is a strain of Bohle iridovirus (BIV), a virus that was first detected in, and thought to be confined to, Australia. Furthermore, marked sequence similarity and genomic co-linearity among ZRV, BIV, and German gecko ranavirus (GGRV) are consistent with the view that all three are strains of Frog virus 3, the type species of the genus Ranavirus, family Iridoviridae.

Here, we report the complete genome sequence of mobuck virus isolated from a Florida white-tailed deer (Odocoileus virginianus) in 2017. This is the second report of mobuck virus in the United States and expands the known geographic range of this novel orbivirus into Florida.

Between 2010 and 2016, six mortality events were observed in Florida pompano (Trachinotus carolinus) maricultured in the Dominican Republic. Histopathological examination and conventional PCR confirmed a megalocytivirus (MCV) infection in each case. Subsequently, next-generation sequencing and phylogenomic analyses confirmed that MCV DNA was present in the infected pompano tissue samples from 2010, 2014, and 2016, and each was determined to be red seabream iridovirus (RSIV). Annotation of the RSIV genome sequences identified 121 open reading frames, and BLASTN analysis revealed the highest nucleotide sequence identity (> 99%) to a RSIV clade 1 MCV isolated from a moribund red seabream (Pagrus major) maricultured in Japan. These cases represent the first fully sequenced RSIV genomes detected outside of Asia and are the earliest reports of MCV infections in Florida pompano. This recent geographical expansion of RSIV warrants further attention to determine its potential economic and ecological impact.

The family Togaviridae comprises several significant human and veterinary mosquito-borne pathogens. Two togaviruses (genus Alphavirus) have been previously identified in association with marine mammals, the southern elephant seal virus (SESV) and Eastern equine encephalitis virus (EEEV) from a fatal captive harbor seal infection. Herein we report the ultrastructural and phylogenomic characterization of a novel marine togavirus, the first isolated from a cetacean, an Alaskan harbor porpoise (Phocoena phocoena) displaying ulcerative dermatitis. A skin sample was processed for virus isolation on Vero.DogSLAMtag cells and cytopathic effects (CPE) were observed on primary isolation approximately 20 days post-infection. Transmission electron microscopy of the infected Vero.DogSLAMtag cells revealed typical alphavirus particles budding from both plasma and vacuolar membranes of infected cells. A next-generation sequencing approach was used to determine the near complete genome of the Alaskan harbor porpoise alphavirus (AHPV). Phylogenetic analysis supported the AHPV as the sister species to the SESV, forming a marine mammal alphavirus clade separate from the recognized alphavirus antigenic complexes. Genetic comparison of the protein coding sequence of the AHPV to other alphaviruses demonstrated amino acid identities ranging from 42.1-67.1%, with the highest identity to the SESV. Based on its genetic divergence, we propose the AHPV represents a novel alphavirus species, pending formal proposal to and ratification by the International Committee on Taxonomy of Viruses. The ecological and genetic characteristics of the AHPV and the SESV also suggest they represent a novel antigenic complex within the genus Alphavirus, which we propose to be named the Marine Mammal Virus Complex. The role of the AHPV in the associated harbor porpoise cutaneous pathology, if any, remains unclear. Further research is needed to determine AHPV's route(s) of transmission and potential vectors, host range, prevalence, and pathogenicity in cetaceans including harbour porpoises.

A lethargic juvenile male harp seal (Pagophilus groenlandicus) in poor nutritional condition was found on the beach on the north shore of Prince Edward Island, Canada, in June 2017. Microscopic examination revealed a severe nonsuppurative encephalitis positive for morbillivirus antigen on immunohistochemistry. Virus isolation attempts were negative. However, phocine distemper virus (PDV) was detected in brain tissue RNA extracts by a seminested reverse transcription PCR that targeted the paramyxovirus RNA-dependent RNA polymerase (pol) gene. Comparison of the resulting partial PDV pol nucleotide sequence revealed it was nearly identical to PDV strains isolated from eastern Atlantic harbor seals (Phoca vitulina vitulina) during a 1988 epizootic in the Wadden and Irish seas, and a western Atlantic harbor seal (Phoca vitulina concolor) that stranded in Maine, US, in 2006. Our study confirmed that closely related PDV strains are circulating in multiple seal species along the coastlines of North America and Europe.

We report the discovery of the first cetacean pegivirus (family Flaviviridae) using a next-generation sequencing approach. One of two infected bottlenose dolphins had elevated activities of liver enzymes, which may suggest hepatocellular injury. Further research is needed to determine the epidemiology and pathogenicity of dolphin pegivirus.

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.

Adenoviruses, papillomaviruses, and polyomaviruses are collectively known as small DNA tumor viruses. Although it has long been recognized that small DNA tumor virus oncoproteins and capsid proteins show a variety of structural and functional similarities, it is unclear whether these similarities reflect descent from a common ancestor, convergent evolution, horizontal gene transfer among virus lineages, or acquisition of genes from host cells. Here, we report the discovery of a dozen new members of an emerging virus family, the Adomaviridae, that unite a papillomavirus/polyomavirus-like replicase gene with an adenovirus-like virion maturational protease. Adomaviruses were initially discovered in a lethal disease outbreak among endangered Japanese eels. New adomavirus genomes were found in additional commercially important fish species, such as tilapia, as well as in reptiles. The search for adomavirus sequences also revealed an additional candidate virus family, which we refer to as xenomaviruses, in mollusk datasets. Analysis of native adomavirus virions and expression of recombinant proteins showed that the virion structural proteins of adomaviruses are homologous to those of both adenoviruses and another emerging animal virus family called adintoviruses. The results pave the way toward development of vaccines against adomaviruses and suggest a framework that ties small DNA tumor viruses into a shared evolutionary history.Author SummaryIn contrast to cellular organisms, viruses do not encode any universally conserved genes. Even within a given family of viruses, the amino acid sequences encoded by homologous genes can diverge to the point of unrecognizability. Although members of an emerging virus family, the Adomaviridae, encode replicative DNA helicase proteins that are recognizably similar to those of polyomaviruses and papillomaviruses, the functions of other adomavirus genes have been difficult to identify. Using a combination of laboratory and bioinformatic approaches, we identify the adomavirus virion structural proteins. The results link adomavirus virion protein operons to those of other midsize non-enveloped DNA viruses, including adenoviruses and adintoviruses.

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.

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).

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.

A group of five juvenile Meller's chameleons (Trioceros melleri) experienced 100% mortality over a period of 1 mo due to ranavirus infection. The index case was found dead without premonitory signs. The three subsequent cases presented with nonspecific clinical signs (lethargy, decreased appetite, ocular discharge) and were ultimately euthanatized. The final case died after initially presenting with skin lesions. Postmortem examination revealed thin body condition in all five animals and mild coelomic effusion and petechiae affecting the tongue and kidneys of one animal. Microscopically, all animals had multifocal necrosis of the spleen, liver, and kidney; four of five animals had necrosis of the nasal cavity; and two of five had necrosis of adrenal tissue, bone marrow, and skin. Numerous basophilic intracytoplasmic inclusions were present in the liver of all animals and nasal mucosa of three of the five animals. Consensus polymerase chain reaction for herpesvirus and adenovirus were negative, whereas ranavirus quantitative polymerase chain reaction was positive. Virus isolation followed by whole genome sequencing and Bayesian phylogenetic analysis classified the isolates as a strain of frog virus 3 (FV3) most closely related to an FV3 isolate responsible for a previous outbreak in the zoo's eastern box turtle (Terrapene carolina carolina) group. This case series documents the first known occurrence of ranavirus-associated disease in chameleons and demonstrates the potential for interspecies transmission between chelonian and squamate reptiles.

Mammalian orthoreovirus (MRV) is the type species of the genus Orthoreovirus and causes a range of significant respiratory, nervous or enteric diseases in humans and animals. In 2016 a farmed white-tailed deer ( Odocoileus virginianus ) fawn became ill, displaying clinical signs of lethargy, dehydration, and profuse foul-smelling diarrhea. A necropsy was performed after the three-week-old fawn died and various tissue samples were submitted to the University of Florida’s Cervidae Health Research Initiative for diagnostic evaluation. Aliquots of homogenized heart, liver, and spleen tissues were inoculated onto Vero E6 cells. After virus-specific cytopathic effects (CPE) were detected in Vero cells inoculated with spleen homogenate, infected cells were fixed in glutaraldehyde and analyzed by transmission electron microscopy (TEM), which revealed icosahedral virus particles approximately 75 nm in diameter with morphologies consistent with those of reoviruses within the cytoplasm of the infected cells. RNA extracted from virions in the spent media of infected cells with advanced CPE was used to prepare a cDNA library, which was sequenced using an Illumina MiSeq sequencer. Complete genome sequences for ten separate reovirus segments were attained, and these indicated the isolated agent was a MRV. Genetic and phylogenetic analyses based on the outer capsid sigma-1 (σ1) protein gene sequences supported the Florida white-tailed fawn isolate as a type 2 MRV that branched as the sister group to a MRV-2 strain previously characterized from the urine of a moribund lion ( Panthera leo ) in Japan. However, analyses based on 7/10 genes (L1-L2, M2-M3, S2-S4) supported the white-tailed deer MRV as the closest relative to a type 3 MRV strain isolated from a dead mink in China. These data suggest the white-tailed deer MRV may have resulted from the natural reassortment of MRVs originating from multiple wildlife species. To our knowledge, this is the first detection of MRV-2 infection in a white-tailed deer. Continued surveillance efforts are needed to determine whether this MRV-2 strain poses a health threat to farmed white-tailed deer populations.

Megalocytivirus is a newly discovered DNA-virus from the Iridoviridae family that possesses icosahedral symmetry and has a size range of 140–200 nm diameter. Based on genetic differences, Megalocytivirus is divided into three major groups; infectious spleen and kidney necrosis virus which is reported to cause disease in numerous marine and freshwater fish species, red sea bream iridovirus that mainly infects red sea bream [Pagrus major (Temminck & Schlegel 1843)] and turbot reddish body iridovirus that is reported to infect Asian flounder species. Megalocytivirus has not been studied as extensively as other genera in the Iridoviridae family until recently; these viruses have received the most attention in research due to the wider host range and cause significant mortality and economic losses in the aquaculture industry. This review provides information on taxonomy, viral properties, epizootic, pathology and diagnostics of Megalocytivirus infection in fish.