In vivo and in vitro, antiviral effects of two mixture of Chinese herbal drug active monomers against MSRV and LMBV in largemouth bass (Micropterus salmoides)

Largemouth bass virus disease (LMBV) and Micropterus salmoides rhabdovirus (MSRV) caused great economic losses to the fish industry. Currently, there are no effective drugs against LMBV and MSRV. Many reports have proved that Chinese herbal drugs (CHDs) possessed antiviral activities. Herein, we investigated antiviral activities of 20 CHD active monomers against MSRV and LMBV in vitro. Results testified that quercetin, coumarin, harpaget, magnolol and hypercin had antiviral activities against LMBV, and chlorogenic acid, quercetin, epigoitrin, limomin and magnolol played remarkable antiviral activities against MSRV. Then, two mixtures drugs of CHD active monomers against MSRV and LMBV were tested and showed noteworthy antiviral activities against MSRV and LMBV in vivo and vitro, respectively. Meanwhile, the two mixtures drugs also increased the expression of type I and type III IFN mediated signal genes. Those results indicated that the two mixtures drugs not only directly inhibited viral replication, but also enhanced its antiviral activity by regulating type I and type III IFN production in largemouth bass, which provided a solid foundation for clinical use of the two mixtures drugs against LMBVD and MSRVD.