Comparative studies of piscine and amphibian iridoviruses

Hyatt, Alex D.; Gould, Allan R.; Županović, Željko; Cunningham, Andrew A.; Hengstberger, S.; Whittington, Richard J.; Kattenbelt, J.; Coupar, Barbara E.H.

doi:10.1007/s007050050025

Cited by 247 publications

(285 citation statements)

References 38 publications

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“…At the same time, size differences between viral particles from gourami and swordtail fish were not significant, which might imply that gouramies and swordtails that cohabited the same farm were crossinfected. Hyatt et al (2000) suggested that differences in particle sizes reflect subdivision within Ranavirus and among iridoviruses. Particle mean v-v from systemic infections observed in our study ranged from 156 to 181 nm, covering nearly the entire range of particle sizes listed by Hyatt et al (2000).…”

Section: Discussionmentioning

confidence: 99%

“…Hyatt et al (2000) suggested that differences in particle sizes reflect subdivision within Ranavirus and among iridoviruses. Particle mean v-v from systemic infections observed in our study ranged from 156 to 181 nm, covering nearly the entire range of particle sizes listed by Hyatt et al (2000). The mean particle size of the iridoviruses from guppies (GV6) and doctor fish (DFV) imported from South East Asia studied in the USA were 162 and 163 nm, respectively (Hedrick & McDowell 1995.…”

Section: Discussionmentioning

confidence: 99%

“…The 7th report of the International Committee on Taxonomy of Viruses confirms the classification of the piscine hematopoietic necrosis viruses as Ranavirus (Williams et al 2000). Data from Hyatt et al (2000) generated from a range of molecular techniques indicate that GV6 and DFV, both imported from South East Asia, are not members of the genus Ranavirus. Hyatt et al (2000) regarded of uncertain taxonomic position the iridovirus-like particles recovered from South East Asian freshwater and marine fish that produce hypertrophic cells in the lamina propria and epidermis, and within organs such as kidney and spleen (Armstrong & Ferguson 1989, He et al 2000, Jung & Oh 2000.…”

Section: Discussionmentioning

confidence: 99%

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Iridovirus infections in farm-reared tropical ornamental fish

Paperna¹,

Vilenkin²,

Matos³

2001

Dis. Aquat. Org.

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A systemic viral infection in both gourami Trichogaster spp. and swordtail Xiphophorus hellerii and an outbreak of lymphocystis in scalare Pterophyllum scalarae and gourami are reported to have occurred in fish reared in ornamental fish farms in Israel. The systemic infection developed in endothelial cells that became hypertrophic and their contents were modified. The presence of such cells in light-microscopically examined stained smears and sections provides an initial indication for this systemic viral infection. Infection in gourami caused hemorrhagic dropsy. Transmission electron microscopic (TEM) images of iridovirus-like particles recovered from gouramies showed them to be 138 to 201 nm from vertex to vertex (v-v); those from swordtails were 170 to 188 nm v-v. TEM images of lymphocystis virions from scalare were 312 to 342 nm v-v and from gourami 292 to 341 nm v-v. Lymphocystis cells from the gourami were joined by a solid hyaline plate, which was lacking in the infection in scalare where the intercellular spaces between the lymphocystis cells consisted of loose connective tissue.KEY WORDS: Trichogaster spp. · Xiphophorus spp. · Pterophyllum scalarae · Iridovirus-like particles · Systemic infection · Endothelium · Hypertrophy · Lymphocystis Resale or republication not permitted without written consent of the publisherDis Aquat Org 48: [17][18][19][20][21][22][23][24][25] 2001 findings together with a demonstration of viral particles by electron microscopy prove to be useful in the differential diagnosis of causes of mortality in the farmed fish. MATERIALS AND METHODSSmears and touch preparations were air-dried, fixed with absolute methanol and stained with Giemsa (in pH 7.4 buffer, for 1 h). For light microscopic histology, tissues were fixed in neutral-buffered formalin (exceptionally with aqueous Bouin's), and after dehydration in graded ethanols were embedded in glycol-methacrylate medium (Agar Scientific, Ltd, Stansted, UK). Sections, 2 to 3 µm, were cut with a glass knife on a Sorval JB4 microtome, and were stained with either Meyer's hemalum-eosin or, after a 20 min incubation in Bouin's solution and a water and 70% ethanol rinse, with 10% Giemsa in phosphate buffer, pH 7.4.For transmission electron microscopy (TEM), fragments from tissue with conspicuous cytopathological changes were fixed in 2.5% glutaraldehyde in cacodylate buffer (0.1 M, pH 7.4) for 24 h at 4°C, rinsed repeatedly in the same buffer, post-fixed in 1.0% osmium tetroxide in the same buffer for 1 h and, after rinsing in the buffer, dehydrated in graded ethyl alcohols and embedded in Agar 100 medium (Agar Scientific, Ltd). Thin sections, cut on a Reichert Ultracut Microtome with a diamond knife, were stained on grid with uranyl acetate and lead citrate, and examined with a Jeol 100CX TEM. Semi-thin sections cut with a glass knife were stained with Toluidine blue. RESULTS Viral hemorrhagic dropsy (VHD) in gouramiAffected fish, observed on several occasions in stocks of farmed gourami of the species Trichogaster trichopter...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Iridovirus infections in farm-reared tropical ornamental fish

Paperna¹,

Vilenkin²,

Matos³

2001

Dis. Aquat. Org.

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“…Ranaviruses (Iridoviridae) are becoming increasingly associated with diseases in wild and cultured fishes, frogs, salamanders, and reptiles (Cunningham et al, 1996;Zupanovic et al, 1998;Hyatt et al, 2000;Zhang et al, 2001;Chinchar, 2002;De Voe et al, 2004;Pearman et al, 2004;Greer et al, 2005). Frog virus 3 (FV3), the best-characterized member and type species of the Ranavirus genus, is a large (165-169 nm) double-stranded DNA icosahedral virus that was originally isolated from the North American leopard frog, Rana pipiens (Chinchar, 2002).…”

Section: Introductionmentioning

confidence: 99%

Xenopus Laevis: A Possible Vector of Ranavirus Infection?

Robert

Abramowitz

Gantress

et al. 2007

Journal of Wildlife Diseases

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ABSTRACT:Frog virus 3 (FV3) or FV3-like viruses (Iridoviridae) infect a wide range of amphibian species, and they are becoming increasingly and causally associated with amphibian disease outbreaks worldwide. We have established the frog Xenopus laevis as an experimental model to study host defense and pathogenesis of FV3 infection. Although X. laevis adults usually clear FV3 infection within a few weeks, viral DNA has been detected in the kidneys several months after they had been experimentally infected; virus also has been detected in seemingly healthy nonexperimentally infected adults. Based on this information, we hypothesized that covert FV3 infection may occur in Xenopus. We first conducted a survey that detected FV3 by polymerase chain reaction (PCR) in the kidneys (the main site of FV3 infection) in a significant fraction of X. laevis raised in five different locations in the United States. Asymptomatic FV3 carriers also were detected by initiation of an acute systemic FV3 infection in frogs that had been immunosupressed by sublethal c-irradiation. Finally, we focused on macrophages as a potential site for viral persistence, and we showed that FV3 can infect peritoneal macrophages in vitro as determined by reverse transcriptase-PCR detection of viral mRNAs. Unlike kidney cell lines that are readily killed by FV3, infected macrophages, like uninfected macrophages, survived up to 12 days. Viral transcription also was detected in macrophages from animals up to 12 days after infection. These results suggest that FV3 can become quiescent in resistant species such as Xenopus, thereby making these species potential viral reservoirs.

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“…We believe that this is not due to insufficient outgroup divergence but due to the limited nature (i.e., possible homology) of the information contained in the partial sequence of the MCP of the virus being analyzed. Historically, short sequences of the MCP have been used to both classify ranaviruses and reconstruct their phylogenetic affinities (e.g., Hyatt et al, 2000), likely because of early evidence that the MCP was a good target for examining the relationships between closely related iridoviruses (Tidona et al, 1998). However, as we have shown in this study, the use of only a section of the MCP gene sequence may be misleading, especially when examining closely related viral isolates.…”

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confidence: 99%