Houttuynia cordata Extract Alleviates SVCV Infection by Modulating the RARα-A/Type I Interferon Axis in Common Carp

Spring viremia of carp virus (SVCV) poses a major threat to aquaculture industry, triggering severe economic losses and substantial damage to fish health. Effective antiviral therapeutic approaches are currently insufficient in aquaculture, highlighting an urgent demand for viable intervention strategies. This study assessed the antiviral and immunomodulatory potential of Houttuynia cordata against SVCV in common carp. Combined cellular and in vivo fish experiments demonstrated that Houttuynia cordata markedly suppresses SVCV replication, reduces viral titer, and enhances disease resistance of carp. The extract appears to suppress RARα-A, upregulate IFN-1/CXCL11, and recruit T lymphocytes via CXCL11, thereby enhancing innate and adaptive immunity against SVCV. Experimental results indicate that Houttuynia cordata alleviates hemorrhagic symptoms induced by SVCV infection. Dietary supplementation with this herb realizes dual functions of viral suppression and immune regulation for carp aquaculture. The findings provide a practical prevention and control strategy against SVCV infection and offer novel insights for research on green antiviral agents. Furthermore, this study verifies the potential value of Houttuynia cordata in improving biological safety and facilitating sustainable development of aquaculture, laying a solid foundation for the development of eco-friendly antiviral preparations.