Study on the Dynamics of Red Sea Bream Iridovirus in Rock Bream (Oplegnathus fasciatus) and Surveillance Methods Utilizing Non-Invasive Methods

Red Sea Bream Iridoviral Disease (RSIVD) is a prevalent infectious disease in South Korea fish farms. Detecting the disease early and preventing its spread through continuous surveillance activities are crucial for disease prevention and management. To achieve this, we utilized a virus concentration method in seawater, providing a non-invasive means to indirectly monitor disease progression. We investigated the viral copy and viral shedding ratio in Oplegnathus fasciatus, known for their high susceptibility to red sea bream iridovirus (RSIV), under flow-through conditions. Horizontal transmission was confirmed in RSIV-infected O. fasciatus and uninfected Lateolabrax japonicus and Acanthopagrus schlegelii. In a flow-through conditions, the mortality rate of O. fasciatus increased with rising water temperature, and it was observed that the maximum viral copy was higher under high-density conditions compared to other density conditions. The study also confirmed horizontal transmission between RSIV-infected O. fasciatus and uninfected L. japonicus and A. schlegelii.