Studi Histopatologi: Pembentukan Sel-Sel Membesar pada Organ Ikan Kerapu Setelah Terinfeksi Megalocytivirus
The genus of Megalocytivirus (family Iridoviridae) isolates GSDIV (grouper sleepy disease iridovirus) is known to cause mass mortality in cultured of grouper and snapper fishes in Indonesia. Histopathologal sign of GSDIV infection was characterized by the formation of enlarged cells in the spleen and kidney. The aim of this study was to know the starting time and development of the formation of enlarged cells in grouper organs after GSDIV infection. A total of 77 juvenile humpback grouper (Cromileptes altivelis) infected with a virus GSDIV intramuscularly. The fish were taken each day for 5 fish and analyzed by histopathology and PCR. Diseased fish showed decreased appetite after 4 days post-infection followed by symptoms of a weak and silent at the base of the tank, as well as the death occurs after 6 to 9 days post-infection with a total mortality of 92%. Histopathological observations showed enlarged cells begin to form on day 3 post-infection that is 40% of the total observed-spleen. The cells were growing in number with increasing time of infection, followed by the spread of these cells to other organs. PCR analysis showed viral DNA GSDIV first detected on day 2 post-infection (20%) and continues to detect with increasing time of infection. Live fish (8%) after 10 days post-infection showed many assemblies of enlarged cells in the spleen and kidney tissues by PCR forward where still contain viral DNA GSDIV. The results showed that the formation of enlarged cells was developed before the fish showed clinical symptoms or death, and fish that can survive after infected GSDIV still contain GSDIV.