Monitoring of viral pathogens in the main Goldfish (Carassius auratus) farms using Immunochemical and Molecular Biology techniques

Diseases are among the most critical threats to the aquaculture industry so that their prevalence leads to major economic losses. Monitoring for viral pathogens in aquaculture has high importance due to their incurability, speed of transmission, the severity of pathogenesis, and difficulties of their diagnosis. According to reports of goldfish ( Carassius auratus ) losses with suspected viral etiology in farms of Gilan province this study designed to inquiring about the existence of selected viral agents. Thus, the spring viremia of carp (SVC) and Koi herpesvirus (KHV) which are among the notifiable infectious diseases (OIE, 2019) were investigated by cell culture, PCR, RT-PCR, and immunofluorescent antibody test (IFAT). The results showed the absence of the RNA of Rhabdovirus carpio and the DNA of Koi herpesvirus in tested samples. Accordingly, 470 bp band related to SVCV and 292 bp band related to KHV were not confirmed in any of the samples in PCR test as well as neither Cytopathic effect in cell culture nor positive reaction in IFAT were observed. Hence, it seems that non-viral agents are the main causes of periodic population loss of goldfish in the surveyed farms and can be controlled and prevented by the health management procedures.