Histopatologi Ikan Kerapu Bebek (Cromileptes altivelis) yang Terinfeksi Iridovirus

Abstract

The humpback grouper (Cromileptes altivelis) is a coral reef fish distributed throughout tropical Asia. The fish has high economic value. However, the production of humpback grouper has been affected by viral diseases including Iridovirus infection. The disease caused mass mortality and decreased the quality and value of humpback grouper. The purpose of this study was to examine the histopathological changes of humpback grouper infected by Iridovirus. The Iridovirus infected grouper samples were received from fish farming in floating net cages in the Mandeh waters, West Sumatra. The fishes showed dark discoloration of the skin, splenomegally and Iridovirus positive PCR test results. The tissues of brain, eye, gill, heart, spleen, intestine, pancreas, liver, kidneys, sceletal muscle, and skin were received in 10% buffered formalin. The histopathological examination showed pathognomonic large intracytoplasmic basophilic inclusion bodies in hematopoietic tissue of spleen and kidney, lymphoid cells were observed in choroid layer of eye and in liver sinusoid. The enlarged cells were present in high numbers in kidney, spleen and liver. Smaller numbers were present in eye, gill, intestine and brain, and none in the heart, pancreas, muscle and skin. Other findings correlated with Iridovirus infection were neuronal ischemic, necrosis of intestinal epithelial cells, necrosis of cardiomyocytes, necrosis of hematopoietic cells of liver and kidney. The literature studies resume that pathogenesis of this viral infection begin with the viral entry through the skin ulcer, then the virus spread systemically in the blood circulation, infect the hematopoietic cells in the spleen and kidney as well as the other cells.