Traditional Chinese medicine bufalin inhibits infectious pancreatic necrosis virus genogroups I and V infection in vitro and in vivo

Infectious pancreatic necrosis virus (IPNV) is the causative pathogen of infectious pancreatic necrosis (IPN), which causes high mortality and great economic losses in salmon and trout aquaculture. IPNVs are divided into seven genotypes, and all IPNV isolates that have been reported in China belong to genogroups I and V. Because of restrictions on imported vaccines, China has no commercial vaccine against IPNV; Therefore, more effective antiviral drugs and vaccines are needed. Traditional Chinese medicine (TCM) has been used to treat endemic and pandemic diseases and is reported effective against viral infections. We screened a TCM library containing 1483 compounds and found that bufalin exhibited anti-IPNV activity. Bufalin inhibits infections from IPNV genogroups I and V by inhibiting viral internalization and RNA replication rather than viral attachment. In vivo results showed that bufalin significantly inhibited viral loads in IPNV-targeted tissues in rainbow trout. Mechanistic research showed that bufalin's antiviral effects occurred via Na+/K+-ATPase. Our results indicate that bufalin inhibits IPNV infections both in vitro and in vivo and may be a promising drug for treating IPNV infections.