Ranavirus

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Ranavirus
Virus classification
Group: Group I (dsDNA)
Order: Incertae sedis
Family: Iridoviridae
Genus: Ranavirus
Species

Ambystoma tigrinum virus
Bohle iridovirus
Epizootic haematopoietic necrosis virus
European catfish virus
Frog virus 3
Santee-Cooper ranavirus

Ranavirus is one of five genera of viruses within the family Iridoviridae, one of the five families of nucleocytoplasmic large DNA viruses. Ranavirus is the only genus within Iridoviridae that includes viruses that are infectious to amphibians and reptiles, and one of only three genera within this family which infect teleost fishes, along with Lymphocystivirus and Megalocytivirus.[1] The ranaviruses, like the megalocytiviruses, are an emerging group of closely related dsDNA viruses which cause systemic infections in a wide variety of wild and cultured fresh and saltwater fishes. As with megalocytiviruses, Ranavirus outbreaks are therefore of considerable economic importance in aquaculture, as epizootics can result in moderate fish loss or mass mortality events of cultured fishes. Unlike megalocytiviruses, however, Ranavirus infections in amphibians have been implicated as a contributing factor in the global decline of amphibian populations. The impact of ranaviruses on amphibian populations has been compared to the chytrid fungus Batrachochytrium dendrobatidis, the causative agent of chytridiomycosis.[2][3][4]

Etymology[edit]

Rana is derived from the Latin for "frog",[5] reflecting the first isolation of a Ranavirus in 1960s from the Northern leopard frog (Lithobates pipiens - formerly Rana pipiens).[6][7][8]

Evolution[edit]

VOA report about Ranavirus

The ranaviruses appear to have evolved from a fish virus which subsequently infected amphibians and reptiles.[9]

Taxonomy[edit]

The family Iridoviridae is divided into five genera which include Chloriridovirus, Iridovirus, Lymphocystivirus, Megalocytivirus, and Ranavirus. The genus Ranavirus is composed of at least 6 recognized viral species, 3 of which are known to infect amphibians (Ambystoma tigrinum virus (ATV), Bohle iridovirus (BIV), and frog virus 3).[10]

Several reptile species are known to be affected:

Structure[edit]

Ranaviruses are large icosahedral DNA viruses measuring approximately 150 nm in diameter with a large single linear dsDNA genome of roughly 105 kbp [19] which codes for around 100 gene products.[20] The main structural component of the protein capsid is the major capsid protein (MCP).

Replication[edit]

Ranaviral replication is well-studied using the type species for the genus, frog virus 3 (FV3).[10][19] Replication of FV3 occurs between 12 and 32 degrees Celsius.[20] Ranaviruses enter the host cell by receptor-mediated endocytosis.[21] Viral particles are uncoated and subsequently move into the cell nucleus, where viral DNA replication begins via a virally encoded DNA polymerase.[22] Viral DNA then abandons the cell nucleus and begins the second stage of DNA replication in the cytoplasm, ultimately forming DNA concatemers.[22] The viral DNA is then packaged via a headful mechanism into infectious virions.[10] The ranavirus genome, like other iridoviral genomes is circularly permuted and exhibits terminally redundant DNA.[22]

Transmission[edit]

Transmission of ranaviruses is thought to occur by multiple routes, including contaminated soil, direct contact, waterborne exposure, and ingestion of infected tissues during predation, necrophagy or cannibalism.[7] Ranaviruses are relatively stable in aquatic environments, persisting several weeks or longer outside a host organism.[7]

Epizoology[edit]

Amphibian mass mortality events due to Ranavirus have been reported in Asia, Europe, North America, and South America.[7] Ranaviruses have been isolated from wild populations of amphibians in Australia, but have not been associated with mass mortality on this continent.[7][23][24]

Pathogenesis[edit]

Synthesis of viral proteins begins within hours of viral entry[20] with necrosis or apoptosis occurring as early as a few hours post-infection.[19][25]

Gross Pathology[edit]

Gross lesions associated with Ranavirus infection include erythema, generalized swelling, hemorrhage, limb swelling, and swollen and friable livers.[7]

See also[edit]

References[edit]

  1. ^ Whittington, RJ; Becker, JA; Dennis, MM (2010). "Iridovirus infections in finfish - critical review with emphasis on ranaviruses". Journal of fish diseases 33 (2): 95–122. doi:10.1111/j.1365-2761.2009.01110.x. PMID 20050967. 
  2. ^ Jancovich, J; Mao, J; Chinchar, VG; Wyatt, C; Case, ST; Kumar, S; Valente, G; Subramanian, S et al. (2003). "Genomic sequence of a ranavirus (family Iridoviridae) associated with salamander mortalities in North America". Virology 316 (1): 90–103. doi:10.1016/j.virol.2003.08.001. PMID 14599794. 
  3. ^ Brunner 2004. Intraspecific reservoirs: complex life history and the persistence of a lethal Ranavirus. Ecology, 85(2), 2004, pp. 560–566.
  4. ^ Pearman, Peter B.; Garner, Trenton W. J. (2005). "Susceptibility of Italian agile frog populations to an emerging strain of Ranavirus parallels population genetic diversity". Ecology Letters 8 (4): 401. doi:10.1111/j.1461-0248.2005.00735.x. 
  5. ^ "http://www.etymonline.com/index.php?term=frog". 
  6. ^ Granoff, A; Came, PE; Rafferty, KA (1965). "The isolation and properties of viruses from Rana pipiens: their possible relationship to the renal adenocarcinoma of the leopard frog". Annals of New York Academy of Science 126 (1): 237–255. doi:10.1111/j.1749-6632.1965.tb14278.x. PMID 5220161. 
  7. ^ a b c d e f Gray, MJ; Miller, DL; Hoverman, JT (2009). "Ecology and pathology of amphibian ranaviruses". Diseases of Aquatic Organisms 87 (3): 243–266. doi:10.3354/dao02138. PMID 20099417. 
  8. ^ Rafferty, KA (1965). "The cultivation of inclusion-associated viruses from Lucke tumor frogs". Annals of New York Academy of Science 126 (1): 3–21. doi:10.1111/j.1749-6632.1965.tb14266.x. PMID 5220167. 
  9. ^ Jancovich, JK; Bremont, M; Touchman, JW; Jacobs, BL (2010). "Evidence for multiple recent host species shifts among the Ranaviruses (family Iridoviridae)". J Virol 84 (6): 2636–2647. doi:10.1128/JVI.01991-09. PMC 2826071. PMID 20042506. 
  10. ^ a b c Chinchar VG, Essbauer S, He JG, Hyatt A, Miyazaki T, Seligy V, Williams T (2005). "Family Iridoviridae" 145-162. In Fauquet CM, Mayo MA, Maniloff J, Desselburger U, Ball LA (eds). Virus Taxonomy, Eighth report of the International Committee on Taxonomy of Viruses. Academic Press, San Diego, USA.
  11. ^ Hyatt AD, Williamson M, Coupar BE, Middleton D, Hengstberger SG, Gould AR, Selleck P, Wise TG, Kattenbelt J, Cunningham AA, Lee J (2002) First identification of a ranavirus from green pythons (Chondropython viridis). J Wildl Dis 38(2):239-252
  12. ^ Benetka V., Grabensteiner E, Gumpenberger M, Neubauer C, Hirschmüller B, Möstl K (2007) First report of an iridovirus (genus Ranavirus) infection in a leopard tortoise (Geochelone pardalis pardalis). Vet Med Austria 94:243–248
  13. ^ Alves de Matos AP, Caeiro MF, Papp T, Matos BA, Correia AC, Marschang RE (2011) New viruses from Lacerta monticola (Serra da Estrela, Portugal): Further evidence for a new group of nucleo-cytoplasmic large deoxyriboviruses (NCLDVs) Microsc. Micoranal 17:101–108
  14. ^ Mao, J; Hedrick, RP; Chinchar, VG (1997). "Molecular characterization, sequence analysis, and taxonomic position of newly isolated fish iridoviruses". Virology 229 (1): 212–220. doi:10.1006/viro.1996.8435. PMID 9123863. 
  15. ^ a b Johnson AJ, Pessier AP, Jacobson ER (2007) Experimental transmission and induction of ranaviral disease in Western Ornate box turtles (Terrapene ornata ornata) and red-eared sliders (Trachemys scripta elegans). Vet Pathol 44(3):285-297
  16. ^ Blahak S., Uhlenbrok C. Ranavirus infections in European terrestrial tortoises in Germany. Proceedings of the 1st International Conference on Reptile and Amphibian Medicine; Munich, Germany. 4–7 March 2010; pp 17–23
  17. ^ Chen ZX, Zheng JC, Jiang YL (1999) A new iridovirus isolated from soft-shelled turtle. Virus Res 63(1-2):147-151
  18. ^ Marschang RE, Braun S, Becher P (2005) Isolation of a ranavirus from a gecko (Uroplatus fimbriatus). J Zoo Wildl Med 36(2):295-300
  19. ^ a b c Williams T, Barbosa-Solomieu V, Chinchar GD (2005). "A decade of advances in iridovirus research" 173-148. In Maramorosch K, Shatkin A (eds). Advances in virus research, Vol. 65 Academic Press, New York, USA.
  20. ^ a b c Chinchar, VG (2002). "Ranaviruses (family Iridoviridae) emerging cold-blooded killers". Archives of Virology 147 (3): 447–470. doi:10.1007/s007050200000. PMID 11958449. 
  21. ^ Eaton HE, Ring BA, Brunetti CR (2010). "The genomic diversity and phylogenetic relationship in the family Iridoviridae." Viruses. 2:1458-1475. http://www.mdpi.com/1999-4915/2/7/1458/pdf
  22. ^ a b c Goorha, R (1982). "Frog virus 3 DNA replication occurs in two stages". Journal of Virology 43 (2): 519–28. PMC 256155. PMID 7109033. 
  23. ^ Speare, R; Smith, JR (1992). "An iridovirus-like agent isolated from the ornate burrowing frog Limnodynastes ornatus in northern Australia". Diseases of Aquatic Organisms 14: 51–57. doi:10.3354/dao014051. 
  24. ^ Cullen, BR; Owens, L (2002). "Experimental challenge and clinical cases of Bohle iridovirus (BIV) in native Australian anurans". Diseases of Aquatic Organisms 49 (2): 83–92. doi:10.3354/dao049083. PMID 12078986. 
  25. ^ Chinchar, VG; Bryan, L; Wang, J; Long, S; Chinchar, GD (2003). "Induction of apoptosis in frog virus 3-infected cells". Virology 306 (2): 303–312. doi:10.1016/S0042-6822(02)00039-9. PMID 12642103. 

External links[edit]

Data related to List of viruses at Wikispecies