During the last two decades, a combination of poor management practices and intensive culturing of penaeid shrimp has led to the outbreak of several viral diseases. White spot disease (WSD) is one of the most devastating and it can cause massive death in cultured shrimp. Following its first appearance in 1992–1993 in Asia, this disease spread globally and caused serious economic losses. The causative agent of WSD is white spot syndrome virus (WSSV), which is a large, nonoccluded, enveloped, rod- or elliptical-shaped, dsDNA virus of approximately 300 kbp. WSSV has a very broad host range among crustaceans. It infects many tissues and multiplies in the nucleus of the target cell. WSSV is a lytic virus, and in the late stage of infection, the infected cells disintegrate, causing the destruction of affected tissues. The WSSV genome contains at least 181 ORFs. Most of these encode proteins that show no homology to known proteins, although a few ORFs encode proteins with identifiable features, and these are mainly involved in nucleotide metabolism and DNA replication. Nine homologous regions with highly repetitive sequences occur in the genome. More than 40 structural protein genes have been identified, and other WSSV genes with known functions include immediate early genes, latency-related genes, ubiquitination-related genes, and anti-apoptosis genes. Based on temporal expression profiles, WSSV genes can be classified as early or late genes, and they are regulated as coordinated cascades under the control of different promoters. Both genetic analyses and morphological features reveal the uniqueness of WSSV, and therefore it was recently classified as the sole species of a new monotypic family called Nimaviridae (genus Whispovirus).
KeywordsWhite Spot Syndrome Virus Internal Ribosome Entry Site Penaeid Shrimp White Spot Syndrome Virus Infection Structural Protein Gene
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- Chen LL, Leu JH, Huang CJ, Chou CM, Chen SM, Wang CH, Lo CF, Kou GH (2002a)Identification of a nucleocapsid protein (VP35) gene of shrimp white spot syndrome virus andcharacterization of the motif important for targeting VP35 to the nuclei of transfected insect cells. Virology 293:44–53CrossRefGoogle Scholar
- Lo CF, Ho CH, Chen CH, Liu KF, Chiu YL, Yeh PY, Peng SE, Hsu HE, Liu HC, Chang CF, Su MS, Wang CH, Kou GH (1997) Detection and tissue tropism of white spot syndrome baculo-virus (WSBV) in captured brooders of Penaeus monodon with a special emphasis on reproductive organs. Dis Aquat Org 30:53–72CrossRefGoogle Scholar
- OIE (World Organisation for Animal Health, formerly Office International des Epizooties)(2003a) Manual of diagnostic tests for aquatic animals, 4th edn. OIE, Paris.Google Scholar
- Robalino J, Bartlett T, Shepard E, Prior S, Jaramillo G, Scura E, Chapman RW, Gross PS, Browdy CL, Warr GW (2005) Double-stranded RNA induces sequence-specific antiviral silencing in addition to nonspecific immunity in a marine shrimp: convergence of RNA interference and innate immunity in the invertebrate antiviral response? J Virol 79:13561–13571PubMedCrossRefGoogle Scholar
- Robalino J, Payne C, Parnell P, Shepard E, Grimes AC, Metz A, Prior S, Witteveldt J, Vlak JM, Gross PS, Warr G, Browdy CL (2006) Inactivation of white spot syndrome virus (WSSV) by normal rabbit serum: implications for the role of the envelope protein VP28 in WSSV infection of shrimp. Virus Res 118:55–61PubMedCrossRefGoogle Scholar
- Tsai MF, Yu HT, Tzeng HF, Leu JH, Chou CM, Huang CJ, Wang CH, Lin JY, Kou GH, Lo CF (2000b) Identification and characterization of a shrimp white spot syndrome virus (WSSV) gene that encodes a novel chimeric polypeptide of cellular-type thymidine kinase and thymi-dylate kinase. Virology 277:100–110CrossRefGoogle Scholar
- Tzeng HF, Chang ZF, Peng SE, Wang CH, Lin JY, Kou GH, Lo CF (2002) Chimeric polypeptide of thymidine kinase and thymidylate kinase of shrimp white spot syndrome virus: thymidine kinase activity of the recombinant protein expressed in a baculovirus/insect cell system.Virology 299:248–255PubMedCrossRefGoogle Scholar
- van Hulten MC, Goldbach RW, Vlak JM (2000a) Three functionally diverged major structural proteins of white spot syndrome virus evolved by gene duplication. J Gen Virol 81:2525–2529Google Scholar
- Venegas CA, Nonaka L, Mushiake K, Shimizu K, Nishizawa T, Muroga K (1999) Pathogenicity of penaeid rod-shaped DNA virus PRDV to Kuruma prawn in different development stages.Fish Pathol 34:19–23Google Scholar
- Wang HC, Lin AT, Yii DM, Chang YS, Kou GH, Lo CF (2003) DNA microarrays of the white spot syndrome virus genome: genes expressed in the gills of infected shrimp. Proceedings of Marine Biotechnology Conference 2003 (P1–045)Google Scholar
- Wang YG, Hassan MD, Sharriff M, Zamri SM, Chen X (1999) Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation. Dis Aquat Org 39:1–11PubMedCrossRefGoogle Scholar
- Wongteerasupaya C, Vickers JE, Sriuairatana S, Nash GL, Akarajamorn A, Boonsaeng V, Panyim S, Tassanakajon A, Withyachumnarnkul B, Flegel TW (1995) A non-occluded, systemic baculovirus that occurs in cells of ectodermal and mesodermal origin and causes high mortality in the black tiger prawn Penaeus monodon. Dis Aquat Org 21:69–77CrossRefGoogle Scholar
- Wu JL, Suzuki K, Arimoto M, Nishizawa T, Muroga K (2002) Preparation of an inoculum of white spot syndrome virus for challenge tests in Penaeus japonicus. Fish Pathol 37:65–69Google Scholar