White Tail Disease of Freshwater Prawn, Macrobrachium rosenbergii.

Macrobrachium rosenbergii is the most important cultured freshwater prawn in the world and it is now farmed on a large scale in many countries. Generally, freshwater prawn is considered to be tolerant to diseases but a disease of viral origin is responsible for severe mortalities in larval, post-larval and juvenile stages of prawn. This viral infection namely white tail disease (WTD) was reported in the island of Guadeloupe in 1995 and later in Martinique (FrenchWest Indies) in Taiwan, the People's Republic of China, India, Thailand, Australia and Malaysia.

Viral diseases of the giant fresh water prawn Macrobrachium rosenbergii: a review.

The giant freshwater prawn Macrobrachium rosenbergii is cultivated essentially in Southern and South-eastern Asian countries such as continental China, India, Thailand and Taiwan. To date, only two viral agents have been reported from this prawn. The first (HPV-type virus) was observed by chance 25 years ago in hypertrophied nuclei of hepatopancreatic epithelial cells and is closely related to members of the Parvoviridae family.

Viral diseases in commercially exploited crabs: a review.

Viruses and viral diseases of crabs were observed and investigated earlier than the first observation of viruses in shrimp. In fact, crabs were used as biological models to investigate crustacean virology at the beginning of shrimp aquaculture development. More than 30 viruses have been reported in crabs, including those related to the known virus families Reoviridae, Bunyaviridae, Roniviridae and a group of Bacilliform enveloped nuclear viruses.

Gene expression kinetics of the yellow head virus in experimentally infected .

The yellow head virus (YHV) has been reported to be one of most pathogenic viruses for cultivated shrimp; however, serious problems have only been reported in farms in south and southeastern Asian. Recently, a YHV strain was detected in cultivated in Mexican farms that lacked virus-associated mortalities or epizooties, and the animals were apparently healthy. The identity of the virus was confirmed by sequencing replicative and structural protein-encoding regions and comparing with homologous virus sequences.

Viral interference between infectious hypodermal and hematopoietic necrosis virus and white spot syndrome virus in Litopenaeus vannamei.

White spot syndrome virus (WSSV) is highly virulent and has caused significant production losses to the shrimp culture industry over the last decade. Infectious hypodermal and hematopoietic necrosis virus (IHHNV) also infects penaeid shrimp and, while being less important than WSSV, remains a major cause of significant production losses in Litopenaeus vannamei (also called Penaeus vannamei) and L. stylirostris (also called Penaeus stylirostris).

Quantitative relationship of two viruses (MrNV and XSV) in white-tail disease of Macrobrachium rosenbergii.

Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) were purified from diseased freshwater prawns M. rosenbergii and used to infect healthy post-larvae (PL) by an immersion method. Three groups of prawns were challenged with various combined doses of MrNV and XSV.

Purification and characterization of infectious myonecrosis virus of penaeid shrimp.

The causative agent of myonecrosis affecting cultured Penaeus vannamei in Brazil was demonstrated to be a virus after purification of the agent from infected shrimp tissues. Purified viral particles were injected into specific pathogen-free P. vannamei, resulting in a disease that displayed the same characteristics as those found in the original shrimp used for purification.

Dot-blot hybridization and RT-PCR detection of extra small virus (XSV) associated with white tail disease of prawn Macrobrachium rosenbergii.

The availability of specific and reliable detection methods is essential for monitoring the health status of farmed species, particularly for viral diseases. Extra small virus (XSV), a virus-like particle, is associated with Macrobrachium rosenbergii Noda virus (MrNV) in white tail disease (WTD) of M. rosenbergii.

Characteristics of the monocistronic genome of extra small virus, a virus-like particle associated with Macrobrachium rosenbergii nodavirus: possible candidate for a new species of satellite virus.

White tail disease (WTD) causes a high mortality rate in the freshwater prawn Macrobrachium rosenbergii. The pathogenic agent is a small virus, 25 nm in diameter, Macrobrachium rosenbergii nodavirus (MrNV), associated with extra small virus (XSV), a virus-like particle,15 nm in diameter. Sequencing of the XSV genome showed that it consists of a linear single-stranded RNA of 796 nucleotides, encoding a single structural protein, the capsid CP-17.

White spot syndrome virus and infectious hypodermal and hematopoietic necrosis virus simultaneous diagnosis by miniarray system with colorimetry detection.

Highly sensitive and specific diagnostic tools are essential for monitoring the health status of farmed species. After the development of genomic probe diagnostic systems in the 1990s, followed by PCR-based systems, a miniarray method has been developed allowing one-step multiple detection. The miniarray method was developed to enable the accessibility of powerful array technology.

Shrimp Taura syndrome virus: genomic characterization and similarity with members of the genus Cricket paralysis-like viruses.

The single-stranded genomic RNA of Taura syndrome virus (TSV) is 10205 nucleotides in length, excluding the 3' poly(A) tail, and contains two large open reading frames (ORFs) that are separated by an intergenic region of 207 nucleotides. The ORFs are flanked by a 377 nucleotide 5' untranslated region (UTR) and a 226 nucleotide 3' UTR followed by a poly(A) tail. The predicted amino acid sequence of ORF1 revealed sequence motifs characteristic of a helicase, a protease and an RNA-dependent RNA polymerase, similar to the non-structural proteins of several plant and animal RNA viruses.