Media, cells and virus strain

Growth medium (GM) used for Vero cell culture was Dulbecco's Modified Eagle Medium (DMEM) supplemented with 5% heat-inactivated fetal bovine serum (FBS) and 1% antibiotic–antimycotic agent mixture (Gibco, Thermo Fisher Scientific, Waltham, USA). Maintenance medium (MM) contained DMEM, 0.3% tryptose phosphate broth (TPB), 0.02% yeast extract and 10 µg/ml of trypsin (Gibco) as a previous report [14]. The PEDV strain of HUA-14PED96 was propagated in Vero cells and used for viral inhibition test [15].