Intranasal infection of CAST mice with LUC-expressing viruses. Groups of four 8–10 week old female mice were infected intranasally with 10, 100, or 1000 PFU of WRvFire, IHD-JvFire, or CPXV-Br-luc. Animals were monitored daily for 24 days for weight loss and death. Weight loss of mice infected with WRvFire (A), IHD-JvFire (B) and CPXV-Br-luc (C); survival of mice infected with WRvFire (D), IHD-JvFire (E), and CPXV-Br-luc (F). Bars represent SEM.