Histological analysis of the lungs. Healthy and affected regions of the lungs were cut out and sectioned for histopathological analysis. Sections were stained using hematoxylin and eosin stain (H&E). Only selected representative sections are shown for each type of affected animal. A, B Sections of healthy regions of the lungs. Normal structure and cellular components of the lungs are visible. C, D Sections of affected regions of the lungs. Loss of structure and heavy lymphocytic infiltrates are readily appreciable.