Research Of Viral Nervous Necrosis Disease In Epinephelus Lanceolatus Grouper

In recent years,viral nervous necrosis disease (VNN) was the serious disease of hatchery-reared grouper in southern Fujian Provinces.The causative agent of VNN was nervous necrosis virus (NNV) and the mortality of grouper larvae and juvenile during disease outbreak were usually aboue 90%, NNV coutains two, single stranded,postive-sense RNA called RNA1 and RNA2. RNA1 encodes RNA dependent RNA polymerase, RNA2 encodes viral coat protein.In our study,real-time fluorescence quantitative everse transcriptase polymerase chain reaction (RRT-PCR) method conducting surveys and research in mariculture grouper areas of southern Fujian Provinces increasingly serious outbreak of infectious diseases in recent years. It explained the grouper aquaculture in the region and its epidemiological characteristics of the main types of infectious diseases. Viral nervous necrosis disease (VNN) is the most common and also the most harmful disease, it often leads to a large number of larval fish and grouper to dead. Apart from the diseased nerve abnormality, no other clinical disorders, and body surface was also no significant pathological changes parasitic or parasites. Various age grouper and the grouper have different susceptibility, it is more harmful to the larvae.A reverse transcriptase polymerase chain reaction (RT-PCR) have been setted to grouper nervous necrosis virus (NNV) detection, investigation of infectious diseases and applied to the import and export of fish disease Xiamen port quarantine. Meanwhile, the brain tissue biopsy method of grouper and the characteristics of retinal lesions verified, RT-PCR have good specificity and sensitivity, capable of detecting nucleic acid level pg volume. Prove that this method is a quick, simple and accurate detection method. The method is applied to the Xiamen sea area to detect more than 10 types of marine fish, found in siganusaramin, acanthopagrus latus infection positive. Note nervous necrosis virus infected grouper and other small other fish in Xiamen City sea area.Using TaqMan probe,Construction of the virus and to contain RNA2 nervous necrosis virus of MS2 bacteriophage genome of the virus as a positive Controls, a TaqMan probe RRT-PCR had been built to dectect grouper nervous necrosis virus, a standard curve have been setted. The correlation coefficient R square is 0.997,Quantitative detection of the virus in the absolute minimum amount of the virus to detect as low as 10 copies. Detection achieved very good results in practice.This paper also determined by the first Epinephelus lanceolatus grouper nervous necrosis virus (MGNNV) RNA1 and RNA2 the entire genome sequence. RNA1 from 3103 nucleotides, containing an open reading frame encoding 982 amino acids, molecular weight of 110.40 Kd.;RNA2 from 1,433 nucleotides. Containing an open reading frame encoding 338 amino acids, the molecular weight of 37.06 Kd. DGNNV RNA1 and RNA2 sequence and the deduced amino acid sequence homology with the other Romania reached a virus gene sequence homology comparison. The results showed that all known grouper nervous necrosis virus genes with high sequence homology. NNV with other fish have a high homology with the homologous virus infected insect Cairo lower. Phylogenetic analysis shows the evolutions of all grouper nervous necrosis virus are at the same level. MGNNV RGNNV genotype is a member.