PATHOGNOMIC DISTRIBUTION OF VIRULENCE VNN (Viral Nervous Necrotic) IN TILAPIA FRY (Oreochromis sp.)

Abstract

Viral Nervous Necrosis (VNN) is a virus that attacks the many marine farmed fish, especially snapper and grouper. Some existing research stating that VNN can also infect several species of freshwater and brackish water fish, one of which tilapia (Oreochromis sp.). The purpose of this study was to determine the genomic VNN on tilapia fry with histopathological analysis and RT-PCR in order to illustrate the distribution of virulence VNN pathognomik qualitatively and quantitatively. The method used in this research is descriptive qualitative. Tilapia fry sample size of 6-8 cm were taken at several locations cultivation of tilapia and a suspect area VNN. Samples were examined clinically and were selected which showed positive PCR results on VNN, then tested its organ damage macroscopically (anatomic pathology) and microscopic (histopathological) and tested the distribution of the virus by RT-PCR. Observations on  the tilapia fry infected with VNN indicate changes and damage to the organs and tissues that can be seen from the examination of clinical symptoms, anatomic pathology and histopathology. Tilapia fry qualitatively (histopathology) showed vacuolization and inclusion body in the organs of the brain and eyes, other damage is also found in liver, kidney, spleen, gills, intestines and muscles; whereas quantitative (RT-PCR) nearly every organ produces positive VNN, except gills and intestines.