Thomas Waltzek - Academia.edu (original) (raw)

Papers by Thomas Waltzek

EDIS

Carp edema virus disease is killing wild and cultured varieties of carp and worrying koi enthusia... more Carp edema virus disease is killing wild and cultured varieties of carp and worrying koi enthusiasts and carp aquaculturists in the United States and around the world. The disease causes skin lesions and swelling and is sometimes called “koi sleepy disease” because infected fish become lethargic and unresponsive. This 6-page fact sheet describes symptoms, diagnosis, prevention, and what fish producers, wholesalers, or retailers can do if they suspect carp may have contracted the disease. Written by Shohreh Hesami, Pedro Viadanna, Natalie Steckler, Staci Spears, Patrick Thompson, Karen Kelley, Roy Yanong, Ruth Francis-Floyd, Johnny Shelley, Joseph Groff, Andy Goodwin, Olga Haenen, and Thomas Waltzek, and published by the School of Forest Resources and Conservation Program in Fisheries and Aquatic Sciences, October 2015. FA189/FA189: Carp Edema Virus Disease (CEVD) / Koi Sleepy Disease (KSD) (ufl.edu)

Journal of Molecular Evolution, 2007

Aromatase cytochrome P450 (P450arom), the enzyme that catalyzes estrogen synthesis, is required f... more Aromatase cytochrome P450 (P450arom), the enzyme that catalyzes estrogen synthesis, is required for successful reproduction and is encoded by a single copy gene (CYP19) in most mammals. However, pigs and their distant suiform relatives the peccaries experienced CYP19 duplication. Here, the evolutionary origin of CYP19 duplication, and the evolution of the gene paralogs, was explored further in collared peccaries (Pecari tayassu). Exons IV and V, and the intervening intron, representing duplicated CYP19 genes, were cloned and sequenced from collared peccary, pig, and hippopotamus. Sequence alignment and analysis identified a gene conversion in collared peccary with a breakpoint 102 base pairs (bp) upstream of exon V. Phylogenetic analyses of nucleotide and amino acid sequence upstream of the breakpoint supported a tree in which one peccary sequence was orthologous with the porcine gonadal gene. Cloning and sequencing of tissue transcripts, using reverse-transcriptase polymerase chain reaction techniques (RT-PCR), confirmed that the gonadal ortholog was expressed in collared peccary testis. Orthology of the other genomic sequence with the porcine placental gene was not resolved, but its placenta-specific expression in collared peccary was confirmed by similar transcript analysis. Immunoblot and enzyme activity in collared peccary testes demonstrated much lower levels of P450arom than in pig testis. Collared peccary placental P450arom expression also seemed much lower than pigs. Thus, suiform CYP19 genes arose from an ancestral duplication that has maintained gonad-and placenta-specific expression, but at lower levels in peccaries than pigs, perhaps facilitating the emergence of different reproductive strategies as Suiformes diverged and evolved.

The Journal of general virology, 2017

The Iridoviridae is a family of large, icosahedral viruses with double-stranded DNA genomes rangi... more 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.

Biology Letters, 2011

Emerging infectious diseases are a significant threat to global biodiversity. While historically ... more Emerging infectious diseases are a significant threat to global biodiversity. While historically overlooked, a group of iridoviruses in the genus Ranavirus has been responsible for die-offs in captive and wild amphibian, reptile and fish populations around the globe over the past two decades. In order to share contemporary information on ranaviruses and identify critical research directions, the First International Symposium on Ranaviruses was held in July 2011 in Minneapolis, MN, USA. Twenty-three scientists and veterinarians from nine countries examined the ecology and evolution of ranavirus–host interactions, potential reservoirs, transmission dynamics, as well as immunological and histopathological responses to infection. In addition, speakers discussed possible mechanisms for die-offs, and conservation strategies to control outbreaks.

Diseases of Aquatic Organisms, 2013

Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacti... more Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacting ornamental and food fish aquaculture. In this report, we characterize a megalocytivirus infection in a captive marine ornamental fish, the orbiculate batfish Platax orbicularis. Histologic examination revealed cytomegalic cells characterized by strongly basophilic granular intracytoplasmic inclusions within various organs. Transmission electron microscopy revealed icosahedral virus particles within the cytoplasm of cytomegalic cells consistent with an iridovirus infection. Analysis of the major capsid protein gene sequence confirmed that the orbiculate batfish virus is a member of the family Iridoviridae and is identical to the only other megalocytivirus reported from a marine ornamental fish, the Banggai cardinalfish Pterapogon kauderni iridovirus.

Ranaviruses, 2015

The genus Ranavirus is a group of globally emerging pathogens infecting fi sh, amphibians, and re... more The genus Ranavirus is a group of globally emerging pathogens infecting fi sh, amphibians, and reptiles, impacting both captive and wild animals. Ranaviruses are pathogens capable of infecting multiple species at a site (e.g., Mao et al. 1999a ;

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

Archives of Virology, 2017

RT-PCR) was designed from this sequence for screening of field samples for FHMCV in the future. T... more 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".

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor... more Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in northwestern Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Viruses 2014, 6 5095 Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

Animals

In spring 2019, diseased four-month-old tilapia (Oreochromis spp.) from an aquaculture farm in So... more In spring 2019, diseased four-month-old tilapia (Oreochromis spp.) from an aquaculture farm in Southern California, USA were received for diagnostic evaluation with signs of lethargy, anorexia, abnormal swimming, and low-level mortalities. At necropsy, non-specific external lesions were noted including fin erosion, cutaneous melanosis, gill pallor, and coelomic distension. Internal changes included ascites, hepatomegaly, renomegaly, splenomegaly, and multifocal yellow-white nodules in the spleen and kidney. Cultures of spleen and kidney produced bacterial colonies identified as Francisella orientalis. Homogenized samples of gill, brain, liver, spleen, and kidney inoculated onto Mozambique tilapia brain cells (OmB) developed cytopathic effects, characterized by rounding of cells and detaching from the monolayer 6–10 days post-inoculation at 25 °C. Transmission electron microscopy revealed 115.4 ± 5.8 nm icosahedral virions with dense central cores in the cytoplasm of OmB cells. A con...

Fish Diseases and Medicine

Proceedings of the Royal Society B: Biological Sciences

Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North At... more Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North Atlantic. PDV has caused two known unusual mortality events (UMEs) in western Europe (1988, 2002), and two UMEs in the northwest Atlantic (2006, 2018). Infrequent cross-species transmission and waning immunity are believed to contribute to periodic outbreaks with high mortality in western Europe. The viral ecology of PDV in the northwest Atlantic is less well defined and outbreaks have exhibited lower mortality than those in western Europe. This study sought to understand the molecular and ecological processes underlying PDV infection in eastern North America. We provide phylogenetic evidence that PDV was introduced into northwest Atlantic pinnipeds by a single lineage and is now endemic in local populations. Serological and viral screening of pinniped surveillance samples from 2006 onward suggest there is continued circulation of PDV outside of UMEs among multiple species with and without...

FACETS

Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectoth... more Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectothermic vertebrates. In this study, we determined the full genomes of eight ranaviruses isolated from marbled sleeper goby ( Oxyeleotris marmorata), goldfish ( Carassius auratus), guppy ( Poecilia reticulata), tiger frog ( Hoplobatrachus tigerinus), Asian grass frog ( Fejervarya limnocharis), and East Asian bullfrog ( H. rugulosus) cultured or imported into Thailand. These ranaviral isolates induced the same cytopathic effects (i.e., progression of coalescing round plaques) in epithelioma papulosum cyprini (EPC) cell cultures. Transmission electron microscopy of infected EPC cells revealed cytoplasmic viral particles with ultrastructural features typical for ranaviruses. Pairwise genetic comparisons of the complete major capsid protein coding sequences from the Thai ranaviruses displayed the highest identity (99.8%–100%) to a ranavirus (tiger frog virus; TFV) isolated from diseased tiger f...

EDIS

Koi herpesvirus (KHV) is a highly contagious virus that causes significant morbidity and mortalit... more Koi herpesvirus (KHV) is a highly contagious virus that causes significant morbidity and mortality in common carp varieties. Common carp is raised as a foodfish in many countries and has also been selectively bred for the ornamental fish industry where it is known as koi. The first recognized case of KHV occurred in the United Kingdom in 1996. Since then other cases have been confirmed in almost all countries that culture koi and/or common carp with the exception of Australia. This 9-page fact sheet is intended to inform veterinarians, biologists, fish producers and hobbyists about KHV disease. Written by Kathleen H. Hartman, Roy P.E. Yanong, Deborah B. Pouder, B. Denise Petty, Ruth Francis-Floyd, Allen C. Riggs, and Thomas B. Waltzek, and published by the UF Department of Fisheries and Aquatic Sciences, April 2013. http://edis.ifas.ufl.edu/vm113

Frontiers in Veterinary Science

The seal picornavirus 1, species Aquamavirus A, is currently the only recognized member of the ge... more The seal picornavirus 1, species Aquamavirus A, is currently the only recognized member of the genus Aquamavirus within the family Picornaviridae. The bear picornavirus 1 was recently proposed as the second species in the genus under the name aquamavirus B. Herein, we determined the complete genomes of two novel pinniped picornaviruses, the harbor seal picornavirus (HsPV) and the ribbon seal picornavirus (RsPV). The HsPV and the RsPV were isolated in Vero.DogSLAMtag cells from samples collected from stranded harbor (Phoca vitulina) and ribbon (Histriophoca fasciata) seals. RsPV-infected Vero.DogSLAMtag cells displaying extensive cytopathic effects were processed for transmission electron microscopy and revealed non-enveloped viral particles aggregated into paracrystalline arrays in the cytoplasm. A next-generation sequencing approach was used to recover the complete genomes of the HsPV and the RsPV (6,709 and 6,683 bp, respectively). Phylogenetic and genetic analyses supported the HsPV and the RsPV as members of the Aquamavirus genus. Based on these results, RsPV represents a novel strain of Aquamavirus A, while the HsPV is a novel strain of the proposed species aquamavirus B. These discoveries provide information on the evolutionary relationships and ultrastructure of aquamaviruses and expands the known host range of those viruses. Our results underscore the importance of the application of classical virology and pathology techniques coupled with high-throughput sequencing technologies for the discovery and characterization of pathogens in wild marine mammals.

EDIS

Tilapia lake virus is a globally emerging virus responsible for episodes of mass mortality in cul... more 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...

Viruses

We report the detection and gene coding sequences of three novel Orbivirus species found in six d... more 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 patho...

Journal of Aquatic Animal Health

Fifteen adult koi (a variant of Common Carp Cyprinus carpio) simultaneously developed white cutan... more Fifteen adult koi (a variant of Common Carp Cyprinus carpio) simultaneously developed white cutaneous proliferations affecting up to 30% of their bodies. The onset of these lesions (in September 2014) was associated with their return to a remodeled backyard water garden after temporarily being maintained in a plastic swimming pool. A single water temperature taken during the outbreak read 21°C on November 17, 2014. The water garden had no extrinsic heat source, with average ambient temperatures ranging from 9.4 to 26.4°C during the outbreak (September 2014-January 2015). Representative skin biopsies were obtained from two fish; the histologic features included severe epidermal hyperplasia, dysplasia, keratinocyte apoptosis, decreased and haphazardly distributed goblet cells with the absence of club cells, keratinocyte hydropic degeneration, and moderate infiltration by lymphocytes and eosinophilic granular cells. Ultrastructural findings included intranuclear nonenveloped hexagonal nucleocapsids and abundant cytoplasmic-enveloped virions morphologically consistent with the Alloherpesviridae family. Polymerase chain reaction was performed on formalin-fixed, paraffin-embedded shavings from the two biopsied koi targeting the thymidine kinase gene of cyprinid herpesvirus 1 (CyHV-1). Together with the aforementioned findings, these results are consistent with an outbreak of CyHV-1 in a population of adult koi.

EDIS

Carp edema virus disease is killing wild and cultured varieties of carp and worrying koi enthusia... more Carp edema virus disease is killing wild and cultured varieties of carp and worrying koi enthusiasts and carp aquaculturists in the United States and around the world. The disease causes skin lesions and swelling and is sometimes called “koi sleepy disease” because infected fish become lethargic and unresponsive. This 6-page fact sheet describes symptoms, diagnosis, prevention, and what fish producers, wholesalers, or retailers can do if they suspect carp may have contracted the disease. Written by Shohreh Hesami, Pedro Viadanna, Natalie Steckler, Staci Spears, Patrick Thompson, Karen Kelley, Roy Yanong, Ruth Francis-Floyd, Johnny Shelley, Joseph Groff, Andy Goodwin, Olga Haenen, and Thomas Waltzek, and published by the School of Forest Resources and Conservation Program in Fisheries and Aquatic Sciences, October 2015. FA189/FA189: Carp Edema Virus Disease (CEVD) / Koi Sleepy Disease (KSD) (ufl.edu)

Journal of Molecular Evolution, 2007

Aromatase cytochrome P450 (P450arom), the enzyme that catalyzes estrogen synthesis, is required f... more Aromatase cytochrome P450 (P450arom), the enzyme that catalyzes estrogen synthesis, is required for successful reproduction and is encoded by a single copy gene (CYP19) in most mammals. However, pigs and their distant suiform relatives the peccaries experienced CYP19 duplication. Here, the evolutionary origin of CYP19 duplication, and the evolution of the gene paralogs, was explored further in collared peccaries (Pecari tayassu). Exons IV and V, and the intervening intron, representing duplicated CYP19 genes, were cloned and sequenced from collared peccary, pig, and hippopotamus. Sequence alignment and analysis identified a gene conversion in collared peccary with a breakpoint 102 base pairs (bp) upstream of exon V. Phylogenetic analyses of nucleotide and amino acid sequence upstream of the breakpoint supported a tree in which one peccary sequence was orthologous with the porcine gonadal gene. Cloning and sequencing of tissue transcripts, using reverse-transcriptase polymerase chain reaction techniques (RT-PCR), confirmed that the gonadal ortholog was expressed in collared peccary testis. Orthology of the other genomic sequence with the porcine placental gene was not resolved, but its placenta-specific expression in collared peccary was confirmed by similar transcript analysis. Immunoblot and enzyme activity in collared peccary testes demonstrated much lower levels of P450arom than in pig testis. Collared peccary placental P450arom expression also seemed much lower than pigs. Thus, suiform CYP19 genes arose from an ancestral duplication that has maintained gonad-and placenta-specific expression, but at lower levels in peccaries than pigs, perhaps facilitating the emergence of different reproductive strategies as Suiformes diverged and evolved.

The Journal of general virology, 2017

The Iridoviridae is a family of large, icosahedral viruses with double-stranded DNA genomes rangi... more 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.

Biology Letters, 2011

Emerging infectious diseases are a significant threat to global biodiversity. While historically ... more Emerging infectious diseases are a significant threat to global biodiversity. While historically overlooked, a group of iridoviruses in the genus Ranavirus has been responsible for die-offs in captive and wild amphibian, reptile and fish populations around the globe over the past two decades. In order to share contemporary information on ranaviruses and identify critical research directions, the First International Symposium on Ranaviruses was held in July 2011 in Minneapolis, MN, USA. Twenty-three scientists and veterinarians from nine countries examined the ecology and evolution of ranavirus–host interactions, potential reservoirs, transmission dynamics, as well as immunological and histopathological responses to infection. In addition, speakers discussed possible mechanisms for die-offs, and conservation strategies to control outbreaks.

Diseases of Aquatic Organisms, 2013

Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacti... more Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacting ornamental and food fish aquaculture. In this report, we characterize a megalocytivirus infection in a captive marine ornamental fish, the orbiculate batfish Platax orbicularis. Histologic examination revealed cytomegalic cells characterized by strongly basophilic granular intracytoplasmic inclusions within various organs. Transmission electron microscopy revealed icosahedral virus particles within the cytoplasm of cytomegalic cells consistent with an iridovirus infection. Analysis of the major capsid protein gene sequence confirmed that the orbiculate batfish virus is a member of the family Iridoviridae and is identical to the only other megalocytivirus reported from a marine ornamental fish, the Banggai cardinalfish Pterapogon kauderni iridovirus.

Ranaviruses, 2015

The genus Ranavirus is a group of globally emerging pathogens infecting fi sh, amphibians, and re... more The genus Ranavirus is a group of globally emerging pathogens infecting fi sh, amphibians, and reptiles, impacting both captive and wild animals. Ranaviruses are pathogens capable of infecting multiple species at a site (e.g., Mao et al. 1999a ;

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

Archives of Virology, 2017

RT-PCR) was designed from this sequence for screening of field samples for FHMCV in the future. T... more 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".

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor... more Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in northwestern Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Viruses 2014, 6 5095 Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

Animals

In spring 2019, diseased four-month-old tilapia (Oreochromis spp.) from an aquaculture farm in So... more In spring 2019, diseased four-month-old tilapia (Oreochromis spp.) from an aquaculture farm in Southern California, USA were received for diagnostic evaluation with signs of lethargy, anorexia, abnormal swimming, and low-level mortalities. At necropsy, non-specific external lesions were noted including fin erosion, cutaneous melanosis, gill pallor, and coelomic distension. Internal changes included ascites, hepatomegaly, renomegaly, splenomegaly, and multifocal yellow-white nodules in the spleen and kidney. Cultures of spleen and kidney produced bacterial colonies identified as Francisella orientalis. Homogenized samples of gill, brain, liver, spleen, and kidney inoculated onto Mozambique tilapia brain cells (OmB) developed cytopathic effects, characterized by rounding of cells and detaching from the monolayer 6–10 days post-inoculation at 25 °C. Transmission electron microscopy revealed 115.4 ± 5.8 nm icosahedral virions with dense central cores in the cytoplasm of OmB cells. A con...

Fish Diseases and Medicine

Proceedings of the Royal Society B: Biological Sciences

Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North At... more Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North Atlantic. PDV has caused two known unusual mortality events (UMEs) in western Europe (1988, 2002), and two UMEs in the northwest Atlantic (2006, 2018). Infrequent cross-species transmission and waning immunity are believed to contribute to periodic outbreaks with high mortality in western Europe. The viral ecology of PDV in the northwest Atlantic is less well defined and outbreaks have exhibited lower mortality than those in western Europe. This study sought to understand the molecular and ecological processes underlying PDV infection in eastern North America. We provide phylogenetic evidence that PDV was introduced into northwest Atlantic pinnipeds by a single lineage and is now endemic in local populations. Serological and viral screening of pinniped surveillance samples from 2006 onward suggest there is continued circulation of PDV outside of UMEs among multiple species with and without...

FACETS

Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectoth... more Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectothermic vertebrates. In this study, we determined the full genomes of eight ranaviruses isolated from marbled sleeper goby ( Oxyeleotris marmorata), goldfish ( Carassius auratus), guppy ( Poecilia reticulata), tiger frog ( Hoplobatrachus tigerinus), Asian grass frog ( Fejervarya limnocharis), and East Asian bullfrog ( H. rugulosus) cultured or imported into Thailand. These ranaviral isolates induced the same cytopathic effects (i.e., progression of coalescing round plaques) in epithelioma papulosum cyprini (EPC) cell cultures. Transmission electron microscopy of infected EPC cells revealed cytoplasmic viral particles with ultrastructural features typical for ranaviruses. Pairwise genetic comparisons of the complete major capsid protein coding sequences from the Thai ranaviruses displayed the highest identity (99.8%–100%) to a ranavirus (tiger frog virus; TFV) isolated from diseased tiger f...

EDIS

Koi herpesvirus (KHV) is a highly contagious virus that causes significant morbidity and mortalit... more Koi herpesvirus (KHV) is a highly contagious virus that causes significant morbidity and mortality in common carp varieties. Common carp is raised as a foodfish in many countries and has also been selectively bred for the ornamental fish industry where it is known as koi. The first recognized case of KHV occurred in the United Kingdom in 1996. Since then other cases have been confirmed in almost all countries that culture koi and/or common carp with the exception of Australia. This 9-page fact sheet is intended to inform veterinarians, biologists, fish producers and hobbyists about KHV disease. Written by Kathleen H. Hartman, Roy P.E. Yanong, Deborah B. Pouder, B. Denise Petty, Ruth Francis-Floyd, Allen C. Riggs, and Thomas B. Waltzek, and published by the UF Department of Fisheries and Aquatic Sciences, April 2013. http://edis.ifas.ufl.edu/vm113

Frontiers in Veterinary Science

The seal picornavirus 1, species Aquamavirus A, is currently the only recognized member of the ge... more The seal picornavirus 1, species Aquamavirus A, is currently the only recognized member of the genus Aquamavirus within the family Picornaviridae. The bear picornavirus 1 was recently proposed as the second species in the genus under the name aquamavirus B. Herein, we determined the complete genomes of two novel pinniped picornaviruses, the harbor seal picornavirus (HsPV) and the ribbon seal picornavirus (RsPV). The HsPV and the RsPV were isolated in Vero.DogSLAMtag cells from samples collected from stranded harbor (Phoca vitulina) and ribbon (Histriophoca fasciata) seals. RsPV-infected Vero.DogSLAMtag cells displaying extensive cytopathic effects were processed for transmission electron microscopy and revealed non-enveloped viral particles aggregated into paracrystalline arrays in the cytoplasm. A next-generation sequencing approach was used to recover the complete genomes of the HsPV and the RsPV (6,709 and 6,683 bp, respectively). Phylogenetic and genetic analyses supported the HsPV and the RsPV as members of the Aquamavirus genus. Based on these results, RsPV represents a novel strain of Aquamavirus A, while the HsPV is a novel strain of the proposed species aquamavirus B. These discoveries provide information on the evolutionary relationships and ultrastructure of aquamaviruses and expands the known host range of those viruses. Our results underscore the importance of the application of classical virology and pathology techniques coupled with high-throughput sequencing technologies for the discovery and characterization of pathogens in wild marine mammals.

EDIS

Tilapia lake virus is a globally emerging virus responsible for episodes of mass mortality in cul... more 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...

Viruses

We report the detection and gene coding sequences of three novel Orbivirus species found in six d... more 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 patho...

Journal of Aquatic Animal Health

Fifteen adult koi (a variant of Common Carp Cyprinus carpio) simultaneously developed white cutan... more Fifteen adult koi (a variant of Common Carp Cyprinus carpio) simultaneously developed white cutaneous proliferations affecting up to 30% of their bodies. The onset of these lesions (in September 2014) was associated with their return to a remodeled backyard water garden after temporarily being maintained in a plastic swimming pool. A single water temperature taken during the outbreak read 21°C on November 17, 2014. The water garden had no extrinsic heat source, with average ambient temperatures ranging from 9.4 to 26.4°C during the outbreak (September 2014-January 2015). Representative skin biopsies were obtained from two fish; the histologic features included severe epidermal hyperplasia, dysplasia, keratinocyte apoptosis, decreased and haphazardly distributed goblet cells with the absence of club cells, keratinocyte hydropic degeneration, and moderate infiltration by lymphocytes and eosinophilic granular cells. Ultrastructural findings included intranuclear nonenveloped hexagonal nucleocapsids and abundant cytoplasmic-enveloped virions morphologically consistent with the Alloherpesviridae family. Polymerase chain reaction was performed on formalin-fixed, paraffin-embedded shavings from the two biopsied koi targeting the thymidine kinase gene of cyprinid herpesvirus 1 (CyHV-1). Together with the aforementioned findings, these results are consistent with an outbreak of CyHV-1 in a population of adult koi.