scholarly journals Characterization of the IFN pathway in the teleost fish gonad against vertically transmitted viral nervous necrosis virus

2015 ◽  
Vol 96 (8) ◽  
pp. 2176-2187 ◽  
Author(s):  
Yulema Valero ◽  
Patricia Morcillo ◽  
José Meseguer ◽  
Francesco Buonocore ◽  
María A. Esteban ◽  
...  
Keyword(s):  
Teleost Fish ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
Viral Nervous Necrosis

Characterization of red-spotted grouper nervous necrosis virus isolated from ovarian fluids of asymptomatic wild Asian seabass, Lates calcarifer

Aquaculture ◽  
2021 ◽  
pp. 736846
Author(s):  
Venkata Satyanarayana Nallala ◽  
M. Makesh ◽  
K. Radhika ◽  
T. Sathish Kumar ◽  
P. Raja ◽  
...  
Keyword(s):  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
Lates Calcarifer ◽  
Asian Seabass

scholarly journals Sea Bass Immunization to Downsize the Betanodavirus Protein Displayed in the Surface of Inactivated Repair-Less Bacteria

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Lama ◽  
Pereiro ◽  
Novoa ◽  
Coll
Keyword(s):  
Culture Media ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Viral Nervous Necrosis ◽  
Casein Hydrolysates

: This work describes immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so-called spinycterin vehicles consisting of irreversibly DNA-damaged DNA-repair-less Escherichia coli displaying at their surface a downsized VNNV coat antigen. In this work we have i) maximized bacterial expression levels by downsizing the coat protein of VNNV to a fragment (frgC91–220) containing most of its previously determined antigenicity, ii) developed a scalable autoinduction culture media for E.coli based in soy-bean rather than in casein hydrolysates, iii) enriched surface expression by screening different anchors from several prokaryotic sources (anchor + frgC91–220 recombinant products), iv) preserved frgC91–220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and v) increased safety using a repair-less E.coli strain as chassis for the spinycterins. These spinycterins protected fish against VNNV challenge with partial (Nmistic + frgC91–220) or total (YBEL + frgC91–220) levels of protection, in contrast to fish immunized with frgC91–220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness and required no adjuvants, thus providing potential to further develop VNNV vaccines for sustainable aquaculture.

scholarly journals Risk factors associated with viral nervous necrosis in hybrid groupers in Malaysia and the high similarity of its causative agent nervous necrosis virus to reassortant red-spotted grouper nervous necrosis virus/striped jack nervous necrosis virus strains

2019 ◽  
Vol 12 (8) ◽  
pp. 1273-1284
Author(s):  
Nurshuhada Ariff ◽  
Azila Abdullah ◽  
Mohamed Noor Amal Azmai ◽  
Najiah Musa ◽  
Sandra Catherine Zainathan
Keyword(s):  
Risk Factors ◽  
Causative Agent ◽  
Life Stage ◽  
Horizontal Transmission ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
Viral Nervous Necrosis ◽  
Hybrid Grouper ◽  
Reassortant Strain ◽  
Associated Risk Factors

Background and Aim: Viral nervous necrosis (VNN) is a serious disease of several marine fish species. VNN causes 100% mortality in the larval stages, while lower losses have been reported in juvenile and adult fish. This study aimed to detect the occurrence of VNN while identifying its associated risk factors and the genotypes of its causative agent in a hybrid grouper hatchery in Malaysia. Materials and Methods: A batch of newly hatched hybrid grouper fry (Epinephelus fuscoguttatus X Epinephelus lanceolatus) were followed from the larval stage to market size. Samples of the hybrid groupers, water, live feed, and artificial fish pellets were collected periodically from day 0 to 180 in the hybrid grouper hatchery. Reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR amplifications were carried out on VNN-related sequences. The phylogenetic tree including the sampled causative agent of VNN was inferred from the coat protein genes from all known Betanodavirus species using Molecular Evolutionary Genetics Analysis (MEGA). Pearson's correlation coefficient values were calculated to determine the strength of the correlation between the presence of VNN in hybrid grouper samples and its associated risk factors. Results: A total of 113 out of 146 pooled and individual samples, including hybrid grouper, water, and artificial fish pellet samples, demonstrated positive results in tests for the presence of VNN-associated viruses. The clinical signs of infection observed in the samples included darkened skin, deformation of the backbone, abdominal distension, skin lesions, and fin erosion. VNN was present throughout the life stages of the hybrid groupers, with the first detection occurring at day 10. VNN-associated risk factors included water temperature, dissolved oxygen content, salinity, ammonia level, fish size (adults more at risk than younger stages), and life stage (age). Detection of VNN-associated viruses in water samples demonstrated evidence of horizontal transmission of the disease. All the nucleotide sequences found in this study had high nucleotide identities of 88% to 100% to each other, striped jack nervous necrosis virus (SJNNV), and the reassortant strain red-spotted grouper NNV/SJNNV (RGNNV/SJNNV) isolate 430.2004 (GenBank accession number JN189932.1) (n=26). The phylogenetic analysis showed that quasispecies was present in each VNN-causing virus-positive sample, which differed based on the type of sample and life stage. Conclusion: This study was the first to confirm the existence of a reassortant strain (RGNNV/SJNNV) in hybrid groupers from Malaysia and Southeast Asia. However, the association between the mode of transmission and the risk factors of this virus needs to be investigated further to understand the evolution and potential new host species of the reassortant strain. Keywords: epidemiology, quasispecies, reassortant, red-spotted grouper nervous necrosis virus-striped jack nervous necrosis virus, viral nervous necrosis.

scholarly journals Fate of Betanodaviruses in the Experimentally Infected Natural and Non-Natural Host

1970 ◽  
Vol 24 (2) ◽  
pp. 100-104 ◽  
Author(s):  
Ghausiatur Reza Banu ◽  
Koh-Ichiro Mori ◽  
Misao Arimoto ◽  
Toshihiro Nakai
Keyword(s):  
Spinal Cord ◽  
Tissue Distribution ◽  
Experimental Period ◽  
Infected Fish ◽  
Natural Host ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
Infectious Dose ◽  
Viral Nervous Necrosis ◽  
Natural Host Species

To investigate the fate of betanodavirus, the causative agent of viral nervous necrosis (VNN) in cultured fish, the tissue distribution of virus in experimentally infected fish was investigated. Two genetically different betanodaviruses, striped jack nervous necrosis virus (SJNNV; SJNNV-genotype) and kelp grouper nervous necrosis virus (KGNNV) belonging to red spotted grouper nervous necrosis virus (RGNNV)-genotype, were intramuscularly cross-injected with a dose of 106 TCID50/fish/200 μl in striped jack Pseudocaranx dentex or kelp grouper Epinephelus moara and sacrificed at scheduled to titre the virus in the spinal cord, brain, eye, kidney and blood at day 0, 1, 3, 5, 14 and 21. As a result, intramuscularly inoculated virus was recovered at high titres from the brain, spinal cord, and eye of their natural host species, i.e., striped jack for SJNNV and kelp grouper for KGNNV during 3-week experimental period, while the virus titres were relatively low in the organs of non-natural hosts, particularly in kelp grouper injected with SJNNV. In every case, no virus was detected in blood samples, suggesting that infection did not develop to be systemic. Keywords: Betanodavirus, Viral nervous necrosis, Fate, Tissue distribution, Pseudocaranx dentex, Epinephelus moara, 50% tissue culture infectious dose (TCID50)DOI: http://dx.doi.org/10.3329/bjm.v24i2.1252 Bangladesh J Microbiol, Volume 24, Number 2, December 2007, pp 100-104

A BIVALENT INACTIVATED VACCINE OF VIRAL NERVOUS NECROSIS VIRUS AND GROUPER IRIDOVIRUS APPLIED TO GROUPER BROODFISH (EPINEPHELUS COIOIDES) REDUCES THE RISK OF VERTICAL TRANSMISSION

2017 ◽  
Vol 43 (03) ◽  
pp. 171-176 ◽  
Author(s):  
Sue-Min Huang ◽  
Jin-Hua Cheng ◽  
Chien Tu ◽  
Tzyy-Ing Chen ◽  
Chun-Ta Lin ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Neutralizing Antibodies ◽  
High Titer ◽  
Serum Antibody ◽  
Pcr Analysis ◽  
Nervous Necrosis Virus ◽  
Epinephelus Coioides ◽  
Necrosis Virus ◽  
Viral Nervous Necrosis ◽  
Level 1

Forty-one broodfish of orange-spotted groupers (Epinephelus coioides) were selected to evaluate the effectiveness of a viral nervous necrosis virus (VNNV) and grouper iridovirus (GIV) inactivated bivalent vaccine in grouper broodfish. Real-time quantitative PCR analysis showed that a detection rate of 10.5% (2/19) was found in egg specimens of VNNV and GIV, which carried approximately 1780 copies of GIV viral DNA in the egg specimens from broodfish before vaccination. This confirmed the vertical transmission route of GIV in broodfish. A significant increase of the anti-VNNV serum antibody titer was more than 50% in the high titer level (1:1810 to 1:5120) and 45% in the moderate titer level (1:452 to 1:1280), which were higher than those of the anti-GIV display, with 50% (10/20) in a titer of 1:57 to 1:320 and 40% (8/20) in a titer of 1:452 to 1:1280 one month after the vaccination. This result showed that the VNNV is a highly antigenic virus and can effectively induce neutralizing antibodies better than GIV. In addition, the VNNV and GIV viral copy numbers were 97.1 and 1780 copies per [Formula: see text]g host egg DNA from the broodfish before vaccination, respectively. One month after the vaccination, the viral genomes of VNNV and GIV were undetectable in egg specimens. The results show that immunization can induce the production of specific protective neutralizing antibodies, and the infective antigens can thereby be eliminated by the immunity. The results demonstrate that the specific antibodies of GIV and VNNV induced by vaccination can reduce the risk of vertical transmission of VNNV and GIV in grouper broodfish.

scholarly journals Near-Complete Genome Sequence of a Fish Nervous Necrosis Virus Isolated from a Clinical Disease Outbreak in Farm-Reared Bream Sparus aurata in Spain

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Panagiota Stathopoulou ◽  
Nausika Rafailidou ◽  
Kostas Tzokas ◽  
Costas Batargias ◽  
George Tsiamis
Keyword(s):  
Phylogenetic Tree ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Viral Genome ◽  
Complete Genome ◽  
Sparus Aurata ◽  
Disease Outbreak ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
Viral Nervous Necrosis

ABSTRACT Sparus aurata larvae infected by viral nervous necrosis were collected from an aquaculture fish farm. The isolated viral genome, composed of two segments (RNA1 and RNA2), was sequenced and analyzed comparatively. Phylogenetic tree analyses revealed that the isolated strain is a reassortant, exhibiting a red-spotted grouper nervous necrosis virus (RGNNV)-type RNA1 and a striped jack nervous necrosis virus (SJNNV)-type RNA2.

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