Inhibitory effect of curcumin on duck tembusu virus

Duck Tembusu virus (DTMUV) is a significant etiological agent responsible for egg production decline in laying ducks and retarded growth in ducklings, contributing to considerable economic losses in the poultry sector. Current research mainly focuses on the development of vaccines for the prevention of DTMUV. However, there is relatively little research on antiviral drugs against this virus. Curcumin has been reported to exert antiviral effects against multiple viruses. However, its efficacy against DTMUV remains unclear. This study aimed to investigate the antiviral activity of curcumin against DTMUV both in vitro and in vivo. Cytotoxicity in BHK-21 cells was assessed utilizing the Cell Counting Kit-8 (CCK-8) assay. The antiviral effects of curcumin were evaluated using viral titration, qRT-PCR, Western blotting, and indirect immunofluorescence. In addition, a DTMUV-infected duck model was used to assess the therapeutic potential of curcumin in vivo. The experimental results indicated that curcumin was non-toxic to BHK-21 cells at concentrations up to 30 μM. In vitro, curcumin significantly reduced DTMUV replication in a dose-dependent manner, as confirmed by decreased viral titers, RNA copy numbers, and E protein expression. Further analysis revealed that curcumin exerted its antiviral effect primarily at the post-adsorption stage of the viral life cycle. In vivo, curcumin treatment improved the survival rate of DTMUV-infected ducklings and alleviated virus-associated pathology. These findings demonstrate that curcumin effectively inhibits DTMUV infection and highlight its potential as a viable candidate for the prevention and treatment of DTMUV-related diseases.