ELECTRON MICROSCOPIC STUDY ON ENLARGED CELLS OF RED SEA BREAM, Pagrus major INFECTED BY THE RED SEA BREAM IRIDOVIRUS (RSIV, GENUS Megalocytivirus, FAMILY Iridoviridae)
Abstract: Most
histopathologycal studies of the red sea bream iridovirus (RSIV) disease in red
sea bream have been performed by studying enlarged cells as well as necrotized
cells in the spleen and other organs. These enlarged cells have been named as
inclusion body bearing cells (IBCs). However, few information is available
about detail of ultrastructural features of IBCs produced in the target organs
of RSIV-infected fish. In the present study, details of ultrastructural
features of IBCs that were produced in the spleen tissue of naturally
RSIV-infected red sea bream were investigated under electron microscope. Under
electron microscope, RSIV-infected red sea bream had the presence of two types
of IBCs: typical IBCs allowing virus assembly within viral assembly site (VAS),
and atypical IBCs which degenerate organelles without virus assembly. Other
infected-cells were observed as necrotized cells forming intracytoplasmic VAS
with large numbers of virions, but without the formation of the distinct
inclusion body. Morphogenesis steps on RSIV-infected red sea bream were observed
as filamentous-filed virions, partially-filled virions and complete virions
with 145-150 nm in size. These findings confirmed that RSIV-infected red sea
bream were characterized by formation of typical and atypical IBCs as well as
necrotized cells.
Keywords: red seabream; RSIV;
INCs; necrotized cells; VAS virion
Author: Ketut Mahardika
Journal Code: jpperikanangg090023