Equine influenza A virus (EIV) of the H3N8 subtype is an important pathogen causing acute respiratory disease in horses.
Peramivir is a selective inhibitor of the influenza virus
neuraminidase (NA). The characteristics of
peramivir are not only its capacity for parenteral administration, but also its strong affinity for NA and slow off-rate from the NA-
peramivir complex, suggesting that it could lead to a prolonged inhibitory effect and thus allow a lower dosing frequency. The aims of this study were to evaluate the inhibitory efficacy of
peramivir against the NA activities of EIV in vitro and the treatment efficacy of a single intravenous dose of
peramivir in horses experimentally infected with EIV.
Peramivir inhibited the activities of NA from the seven contemporary EIV strains in vitro, with 50% inhibitory concentrations ranging from 0.10 to 0.20 nmol/L. Horses treated with a single IV dose of
peramivir (3,000 mg/600 mL/animal, 7.8-9.3mg/kg of bodyweight) showed significantly milder clinical signs (
pyrexia, nasal discharge and
cough) with a shorter duration than control horses injected with
normal saline. Moreover, the mean duration of virus shedding for the horses treated with
peramivir was significantly shorter than for the control horses. These findings suggested that a single IV administration of
peramivir had good potential for the treatment of equine
influenza, and may help to limit the spread of the disease in the horse population.