Demonstrating the Importance of the Emergence of the S7 Gene in Monitoring GCRV-II Environmental Transmission

Grass carp reovirus is a major aquaculture biosecurity threat, causing acute outbreaks and diagnostic delays in hemorrhagic disease. For early warning of GCRV-II in aquaculture water, this study established a method using iron flocculation to concentrate viruses, with qPCR-based tracking and viral load quantification. Results show the S7 gene serves as a highly sensitive and stable monitoring marker, suitable for efficient water surveillance. Furthermore, viral load in aquaculture water negatively correlated with fish survival and pathology, validating environmental monitoring as an effective early-warning system for disease outbreaks. This provides an efficient molecular marker for GCRV-II monitoring and control.