PATHOGENECITY OF GROUPER SLEEPY DISEASE IRIDOVIRUS (GSDIV: Megalocytivirus, FAMILY Iridoviridae) TO CORAL TROUT GROUPER Plectrophomus leopardus
Abstract: Grouper sleepy disease
iridovirus (GSDIV), a member of the genus Megalocytivirus in the family
Iridoviridae, has been known to cause large scale mortalities resulting in
severe economic losses in grouper industries in south-east Asia including
Indonesia. In this study, experimental infection of coral trout grouper
Plectrophomus indicus with GSDIV was performed to evaluate the viral
pathogenecity to this fish species. After virus exposure, the mortalities of
coral trout grouper injected with primary and 10-1 dilution of spleen
homogenates derived from tiger grouper Epinephelus fuscoguttatus were 100% and
90%, respectively. Histopathology revealed that moribund fish receiving GSDIV
inoculum displayed massive formation of enlarged cells in the spleen and
hematopoitic tissues. Under electron microscopy, the enlarged cells were
observed as inclusion body bearing cells (IBCs) and necrotic cells allowing
virus propagation within an intracytoplasmic virus assembly site (VAS). GSDIV
virions were 167-200 nm in size. These findings confirmed that GSDIV has severe
pathogenicity to coral trout grouper and IBCs as well as necrotic cells were
determined to be the pathognomonic sign of megalocytivirus-infected coral trout
grouper.
Keywords: coral trout grouper;
GSDIV; IBCs; Megalocytivirus; Necrotic cells
Author: Ketut Mahardika, Ahmad
Muzaki, Ketut Suwirya
Journal Code: jpperikanangg090031
