PICV, strain An 4763, was provided by Dr. David Gangemi (Clemson University, Clemson, South Carolina). The virus was passaged once through hamsters. Virus stocks were prepared from pooled livers harvested from infected hamsters. Virus dilutions were made in minimal essential medium (MEM), and infectious inoculum was given bilaterally in two intraperitoneal (i.p.) injections of 0.1 mL each. The recombinant adenovirus vectored cIFN-a (rAd5-huIFN-a; DEF201) and the rAd5 empty vector (rAd EV) control virus were provided by Defyrus, Inc. (Toronto, ON, Canada) at a concentration of 6610 9 and 2610 11 plaque-forming units (pfu)/ml, respectively. Both viruses were prepared in PBS for i.n. instillation in a 200 ml volume.