Aquatic Animal Viruses and Antiviral Immunity

The Special Issue on Aquatic Animal Viruses and Antiviral Immunity highlights the remarkable diversity of viruses circulating in marine and freshwater systems and the equally diverse responses of their hosts. Across its contributions, the issue reveals how persistent, emerging, and previously unrecognized viruses shape the health of wild and farmed aquatic species. Several studies uncover long-term or cryptic viral infections in fish populations, showing how pathogens can endure across years and influence conservation and hatchery management. Other articles describe newly detected or genetically distinct viruses in economically important species, underscoring the continual emergence of threats in aquaculture. Advances in diagnostics and surveillance also feature prominently, including practical tools for monitoring immunity and infection at the farm level. Mechanistic work further deepens understanding of how viruses manipulate host cells, illuminating pathways that may offer future intervention potential. Collectively, the Special Issue brings together ecological, molecular, and applied perspectives to illustrate how aquatic viruses evolve, spread, and interact with their hosts. It offers a timely synthesis for researchers, managers, and industry stakeholders committed to improving fish health and sustaining resilient aquatic ecosystems.