Grouper viruses

Hegde, A., Chen, C.L., Qin, Q.W., Lam, T.J. and Sin, Y.M. (2002). Characterization, pathogenicity and neutralization studies of a nervous necrosis virus isolated from grouper, Epinephelus tauvina, in Singapore. Aquaculture 213: 55-72.

Abstract: A virus isolated from diseased marine fish, Grouper, Epinephelus tauvina, was cultured in sea bass (SB) cell line, characterized and its pathogenicity and neutralization studies were carried out. This isolated virus is an icosahedral virus with a mean diameter of 28-30 nm and has buoyant density of 1.30-1.35 g/ml. It replicates exclusively in the cytoplasm and forms paracrystalline array and inclusion bodies in the infected cells. SDS-PAGE analysis of purified virus structural proteins resolved one major polypeptide of approximately 42 kDa. This virus induces cytopathic effects such as rounding and granulation of cells, localized cell death and detachment of cells within 3-5 days postinfection on sea bass larval cell line. Typical histopathological changes in the virus-infected sea bass larvae under experimental conditions showed vacuolation of nervous tissue. Polyclonal antisera raised against the purified virus and the coat protein of this virus effectively neutralized virus infectivity in vitro suggesting the use of coat protein as a vaccine against this viral infection.

Virus name: unnamed

Host: Malabar grouper, Epinephelus malabaricus

Boonyaratpalin, S., Supamattaya, K., Kasornchandra, J. and Hoffmann, R.W. (1996). Picorna-like virus associated with mortality and a spongious encephalopathy in grouper Epinephelus malabaricus. Dis. Aquatic Org. 26: 75-80.

Abstract: A picorna-like virus was detected from diseased fry and fingerling grouper Epinephelus malabaricus cultured in southern Thailand. Affected grouper exhibited dark coloration of the head and tail, loss of equilibrium and corkscrew-like swimming. Pathological changes of affected fish showed vacuolating encephalopathy and retinopathy. Intracytoplasmic inclusions were observed in the nerve cells. From electron microscopic studies, virus particles could be detected in the brain and eyeball of affected fishes. They were round to icosahedral, without an envelope, 20 to 25 nm in diameter and had an electron dense core of 16 nm. Filtrates (0.45 pm) of affected brain and eyeball tissues can produce the same clinical signs in healthy grouper after injection, and the identical virus particles could be observed in the brain and retina of experimentally infected fish.