Dynamics of infection after contact transmission and subsequent challenge.

One 129X1 mouse inoculated intranasally with 70-PFU of rSeV-luc(M-F*) was placed in a cage with 3 naïve mice 24 hours later. Bioluminescence in the (A) nasopharynx, (B) trachea, and (C) lungs was measured daily in the contact mice until infection was cleared (on average 14 days). Seventy days after inoculation of donor mice, the recipients were challenged with 3×10⁶ PFU of rSeV-luc(M-F*) so that reinfection could be monitored by bioluminescence. Each individual mouse is color-coded (n = 6). The bottom of the y-axis is 5.5×10⁵ photons/s, the limit of detection of bioluminescence.