Macroscopic and microscopic lung findings. Pictures show the macroscopic lung appearance A at necropsy of representative control (left), 3249 (middle) and Lena (right) animals euthanised at 13 dpi. Lungs from 3249 (middle) and Lena (right) infected pigs shown tan-mottled areas, atelectasis, rubbery consistency, but also consolidated areas are observed in cranial apical and middle lung lobes in Lena-infected pigs (right) (white arrows). Photomicrographs of the middle lung lobe B from control (left), 3249 (middle) and Lena (right) pigs euthanised at 13 dpi (H&E; bars 50 μm). Lung from 3249 (middle) and Lena (right) representative infected piglets show a moderate interstitial pneumonia characterised by thickening of the alveolar septa due to infiltrating lymphocytes and macrophages. Moreover, Lena-infected lung (right) exhibits extensive foci of suppurative bronchopneumonia with neutrophils, cellular debris, and multifocal chromatin clumps (arrow-head). Graphs display macroscopic C and microscopic D lung lesion score of each animal along the study. Bars indicate median values for each group.