Abstract. Wahidi BR, Yanuhar U, Fadjar M, Andayani A. 2019. Pathognomonic features and ultrastructural of Koi Herpesvirus infected Oreochromis niloticus. Biodiversitas 20: 497-503. Koi Herpesvirus (KHV) has caused considerable losses in the cultivation of the Cyprinidae family worldwide. In addition to infecting Cyprinidae, KHV can also infect other freshwater fish. This study reports histopathology and ultrastructural analysis of KHV that infect Nile tilapia. Although there are no specific clinical symptoms, pathognomonic indicating Nile tilapia fish has been infected with KHV have been found, i.e. through the formation of intranuclear inclusion body and cell swelling which essentially experience chromatin margination. In addition, histopathology results indicate changes or damage to other tilapia tissue, i.e. necrosis, hypertrophy, edema, hemorrhage, inflammation, congestion, degeneration, and apoptosis. These results indicate that KHV has been distributed and replicated in tilapia organs. Based on the Transmission Electron Microscopy (TEM) analysis, KHV virions have been detected in the cytoplasm or outside the cells on a size of 150-170 nm.

Clarias gariepinus is one of the freshwater fish that is easy to culture, but is also susceptible to Edwardsiella tarda infection. Although this is convenient to treated, the consequences of this bacterial infection are quite detrimental. The method used in this study is a biochemical test followed by histopathological examination to observe tissue changes that occur in the Clarias gariepinus organ. The results showed that 5 out of 17 samples were infected with Edwardsiella tarda with pathological features showing edema, congestion, lymphocyte infiltration, macrophage proliferation, and necrosis in all organs.

Koi Herpesvirus ( KHV ) is a virus that infects goldfish and koi that resulted in mass death and cause economic and social losses. The use of Polymerase Chain Reaction (PCR) technique to detect KHV was done  in nila and gurame. Proof that KHV could infect nila and gurame KHV following genetic variation in each definitive host and spreading area have not been done. Based on these problems, this research was conducted to study the genetic variability and genetic relationships between KHV isolates in some freshwater fish as the definitive host koi, komet , koki, nila and gurame that exist in the area of East Java. The results showed that clinically the gills were pale and hemorrage the end of the tail fin. Electrophoresis results showed that all samples from  KHV infected  koi, koki, komet, nila and gurame  were all  positive but the sequencing results for tilapia and carp could not be further identified using the BLAST program. Genetically,  koi fish, koki and komet isolates were identical to GenBank isolates code KHV-GZ11 and Indo_0K02SS.

Histamin merupakan salah satu indikator keamanan mutu pangan untuk produk olahan ikan. Histamin dimungkinkan terkandung pada ikan pindang karena beberapa faktor. Penelitian ini bertujuan untuk mengetahui kadar histamin pada ikan pindang yang dijual dan dikonsumsi oleh masyarakat serta faktor-faktor yang mempengaruhi terbentuknya dan kenaikan kadar histamin pada ikan pindang. Sampel ikan pindang diperoleh dari beberapa pasar tradisional di Sidoarjo dan diuji menggunakan metode ELISA. Hasil uji terhadap beberapa parameter menujukkan bahwa nilai pH berkisar antara 6,05 – 6,95; kadar air 13,11 – 27,79%; kadar garam 6,71 – 12,31%; dan kadar histamin 4,143 – 11,450 ppm. Kadar histamin tertinggi diperoleh dari sampel ikan pindang dengan kadar air yang tinggi dan kadar garam yang rendah.

Koi herpesvirus (KHV) not only can infect cyprinidae, but also infect other freshwater fishes. It causes KHV to spread widely throughout the world. Infection of KHV in fish has several symptoms and one of them is increased HSP70 expression. The purpose of this study is to detect HSP70 expression in KHV-infected tilapia. The study were carried out by qualitatively examining expression of HSP70 in the gill of tilapia, both normal tilapia and KHV-infected tilapia, and by detecting the tissue damage caused by KHV by means of histopathology. The results of this study show that HSP70 was detected in fish that were infected by KHV, while in control fish, HSP70 was not detected. This result indicates that tilapia infected by KHV experience an increase in HSP70 expression. Damage to the gill of tilapia is also one of the responses to KHV antigens in the host cell. Thus, this study presumed that KHV infection in tilapia is influenced by the expression of HSP70.