In vitro efficacies of oseltamivir carboxylate and zanamivir against equine influenza A viruses

Abstract

To investigate the possibilities of two NA inhibitors [oseltamivir carboxylate (OC) and zanamivir (ZA)] as the clinical agents for equine nifluenza A virus (EIV) infection, we examined the efficacies of these inhibitors against twelve EIVs in vitro. OC and ZA inhibited NA activities of all EIVs with 50% inhibitory concentrations with ranging from 0.017 to 0.130 and from 0.010 to 0.074 μM, respectively. OC and ZA inhibited plaque-forming of all EIVs in MDCK cells with 50% effective concentrations with ranging from 0.015 to 0.097 and from 0.016 to 0.089 μM, respectively, except for one strain (13.328 μM and 6.729 μM). These results suggest that these inhibitors are effective against most EIVs and might be useful for treatment of EI in horses.