Primary infection and secondary reinfection in individual mice after airborne transmission across a 7.6-cm separation.

In vivo bioluminescence was measured in individual animals after airborne exposure to donor mice that had been directly inoculated with 70 or 7,000 PFU of rSeV-luc(M-F*). All mice were challenged on day 70 of the experiment with a lethal 3×106-PFU dose of rSeV-luc(M-F*). Mice involved in the airborne transmission experiments were categorized based on the dynamics of the resultant infection: (A) no transmission (1–3), (B) non-productive infection (4), (C) tracheal dominant (5–12), (D) respiratory disseminated with nasopharyngeal first (13–16), and (E) respiratory disseminated with tracheal first (17–21). (F) Bioluminescence curves for two representative mice infected by contact transmission are also included. The bottom of the y-axis is 5.5×105 photons/s, the limit of detection of bioluminescence.