FURIN and infection: Vero cells were treated either with a furin inhibitor (decanoyl-arg-val-lys-arg-chloromethylketone [CMK]), a serine protease inhibitor (camostat [cam]), or a cysteine protease inhibitor (E64) under four different conditions: (1) 1 h prior to infection; (2) 1 h prior to infection and for 2 h during infection; (3) 1 h prior to infection and for 72 h p.i.; and (4) 2 h p.i. to 72 h p.i..