Post-exposure prophylaxis experiment. The design was similar to the DEF201 pre-exposure prophylaxis experiment with the following differences. Single dose i.n. treatments with 10 8 pfu of DEF201 or rAd EV were administered 24 h prior to, or 6, 24, or 48 h after challenge with ,5 pfu of PICV. On day 28 postinfection, the surviving animals (including 6 naïve sham-infected controls) were re-challenged. Morbidity and mortality were observed out to 58 days after the initial challenge.