S. Boonyaratpalin et al., PICORNA-LIKE VIRUS-ASSOCIATED WITH MORTALITY AND A SPONGIOUS ENCEPHALOPATHY IN GROUPER EPINEPHELUS-MALABARICUS, Diseases of aquatic organisms, 26(1), 1996, pp. 75-80
A picorna-like virus was detected from diseased fry and fingerling gro
uper Epinephelus malabaricus cultured in southern Thailand. Affected g
rouper exhibited dark coloration of the head and tail, loss of equilib
rium and corkscrew-like swimming. Pathological changes of affected fis
h 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 o
f 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. Fil
trates (0.45 mu m) of affected brain and eyeball tissues can produce t
he same clinical signs in healthy grouper after injection, and the ide
ntical virus particles could be observed in the brain and retina of ex
perimentally infected fish.