By 1 DPI, an area of consolidation was identified on CT in the right caudal lobe with corresponding radiotracer uptake on PET (Fig. 2B , SUVMax of 4.7). Consolidative areas in the right caudal lobe increased by day 2, with a persistently elevated SUVMax of 3.1(data not shown). By day 3, the consolidation increased in the right caudal lobe ( Fig. 2C and Fig. 3C , SUVMax of 3.7 and 4.4, respectively) and also appeared in the left caudal lobe (SUVMax of 3.2) of ferret 2214 (Fig. 3C ). By 6 DPI, there were widespread areas of patchy consolidation on CT with multiple areas of increased radiotracer uptake in both ferrets in caudal and cranial lobes ( Fig. 2D and Fig. 3D , SUVMax of 6.0 and 7.6 on the right, 4.2 and 4.6 on the left, respectively). These results suggest that inflammation progresses into the lower respiratory airways after infection into the upper part of the lower respiratory system. A ferret from the uninfected cohort was also imaged on day 6, with no focal appearance of consolidation on CT and no evidence of increased [ 18 F]-FDG uptake on PET (image not shown, background SUV of 0.6).