Many scientists talked about first report of VNN in marine fish In many of scientific reports such as:
1) The first report of viral infection in Asian sea bass was made by Glazebrook et al. (1990), who described a picorna-like virus associated with mortalities of 15 to 20 d old larvae. This disease was also investigated by Munday et al. (1992) in Asian sea bass and is now recognized as being caused by a piscine nodavirus (Azad et.al., 2005).
2) Also, according to first record of VNN in North America by (Curtis et al., 2001), the viral aetiology of mass mortalities of white seabass, Atractoscion nobilis, cultured in southern California, USA was examined. Disease outbreaks occurred in juvenile fish reared at two culture facilities from June to December 1999, with clinical signs such as anorexia and erratic swimming motion. Microscopic lesions observed in moribund fish included marked vacuolation of brain, spinal cord and retina. The piscine nodavirus (Betanodavirus), the causative agent of viral nervous necrosis (VNN), was detected in the affected tissues by electron microscopy, indirect fluorescent antibody test (IFAT), reverse transcription–polymerase chain reaction (RT–PCR), and isolation in cell culture. The agent was identified as one of the four known genotypes of piscine nodavirus. In addition, a similar nodavirus was also detected in fish samples from disease outbreaks at the same facility in 1992. In the last decade, VNN has been reported among cultured populations of marine fish worldwide and this paper is the first record of the agent in North America (Curtis et al., 2001).
Meanwhile, we succeed to isolate and identify of VNN virus as first time in Golden grey mullet (Liza auratus) in the Caspian Sea in 2004 (as attached article).
Furthermore, according to knowledge of my dear friend, Prof. G. Bovo from OIE reference Lab. of VNN, he showed me in EAFP 2013 Conference in Split, Croatia a document about first report of VNN in Senegal in 1996 (In second attached file).
What do you think about original and correct time about first outbreak or occurrence of VNN in the world?
Thanks again
Its rather an interesting question. Though early reports of virus induced brain and eye lesions were published (such as Glazebrook et al. 1990; Munday et al 1992) the virus causing Viral Encephalopathy and Retinopathy or VNN was first identified as a member of Nodaviridae following purification of virus from brain tissues from affected striped jack larval, following which some molecular characterisation was undertaken and the name striped jack nervous necrosis virus (SJNNV) was adopted (Mori 1992).
With all of the viruses, early reports and TEM studies are not now considered definitive until the virus involved has been characterised by molecular means. So, for example, Oyster herpesvirus, described in the literature from the 1970's, is not considered to be OSHV1, but "OSHV1 - like" virus. So VNN that was seen by histology or TEM or cell culture and which has not been characterised by molecular means is "VNN-like" in modern literature. Indeed, we now know that there is considerable variation in the genome - leading to recognition of four genotype clusters.
Its rather an interesting question. Though early reports of virus induced brain and eye lesions were published (such as Glazebrook et al. 1990; Munday et al 1992) the virus causing Viral Encephalopathy and Retinopathy or VNN was first identified as a member of Nodaviridae following purification of virus from brain tissues from affected striped jack larval, following which some molecular characterisation was undertaken and the name striped jack nervous necrosis virus (SJNNV) was adopted (Mori 1992).
With all of the viruses, early reports and TEM studies are not now considered definitive until the virus involved has been characterised by molecular means. So, for example, Oyster herpesvirus, described in the literature from the 1970's, is not considered to be OSHV1, but "OSHV1 - like" virus. So VNN that was seen by histology or TEM or cell culture and which has not been characterised by molecular means is "VNN-like" in modern literature. Indeed, we now know that there is considerable variation in the genome - leading to recognition of four genotype clusters.
Dear John,
Thanks for your valued and clear response. According to your opinion molecular diagnosis technique and design of phylogenic pattern of each unknown viral causative agents should be essential method for isolation and final confirmation of them.
Yes but its not just my opinion. I have found many oyster herpesvirus by TEM before 1990 but the scientific community and the OIE will not accept that they are OSHV1. Likewise I spoke to T. Miyazaki about iridovirus and he agrees that today molecular confirmation of identity is essential.
One of my respected colleagues Dr. Kjersti Gravningen from Norway sent me this valued comment as follows:
"We named "picornavirus-like" in turbot in Norway in 1991 - this was later confirmed being VNN. Block et al. Diseases of Aquatic organisms 10 65-70, 1991."
Dear Jalil,
Can't comment on outbreaks or first occurence of viral induced VNN but I would like to point you to another article (report) the findings of which must have been made in 1991 and perhaps earlier due to its publication date (see below, *) ):
Properties of a new virus belonging to nodaviridae found in larval striped jack (Pseudocaranx dentex) with nervous necrosis.
by: Mori K, Nakai T, Muroga K, Arimoto M, Mushiake K, Furusawa I.
in: Virology. 1992 Mar;187(1):368-71.
Only for (your) convenience:
Abstract
Spherical virus particles were purified from larval striped jack (Pseudocaranx dentex) with nervous necrosis. The virus consists of nonenveloped particles, about 25 nm in diameter, and contains two single-stranded, positive-sense RNA molecules with molecular weights of 1.01 x 10(6)Da (RNA 1) and 0.49 x 10(6)Da (RNA 2), respectively. The RNAs do not have poly(A) sequences at the 3' terminus. Virus structural proteins consist of two proteins with molecular weights of 42 and 40 kDa. When translated into cell-free extracts of rabbit reticulocytes, RNA 1 directed the synthesis of the 1a protein (100 kDa), whereas RNA 2 synthesized the 2a protein (42 kDa), which is probably the coat protein of the virus, and a polypeptide of 40 kDa which appears to be the processed form of the 42-kDa protein. Under electron microscopic observation, the virus particles were found in the tissues of the central nervous system of the affected larval striped jack. From morphological and biochemical properties of the virus, we identified this virus as a new member of the family of Nodaviridae and designated it striped jack nervous necrosis virus.
cf: https://www.ncbi.nlm.nih.gov/pubmed/1736540
*) ohhh... Now that I've read more closely again the first answer by John Brian Jones I regret that I overlooked his mentioning already the article of Mori... but I don't want to delete now my "elaborate"...also because "the virus causing Viral Encephalopathy and Retinopathy or VNN was first identified as a member of Nodaviridae by MORI et al, then published March 1992...) (:-))
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