Figure 5.

Spread of alveolar infection from a 1 mL bolus with 10⁶ infectious virions versus a submicrometer aerosol with one infectious virion. (A) The purple circle represents a 1 mL bolus (radius = 37,550 μm), assumed to infect all AT2 cells below the patch at the start of day 0. The orange circle that slightly expands the purple circle represents the region of cells the bolus infects after 7 days (radius=38,670 μm). (B) A single dot in the 10 × 10 cm box represents an aerosol with one infectious virion assumed to infect a single cell at the start of day 0. The orange circle represents the region of cells the single virion infects after 7 days (radius=1120 μm). The inset image expands a 3 × 3 mm region of the 10 × 10 cm square, and at this magnification the purple dot at the center is still nearly imperceptible.