Table 1 Histopathology of cattle lung lesions following aerogenous infection with M. bovis.
Histopathology of cattle lung lesions following aerogenous infection with M. bovis | Classical granuloma | Invasive necrotizing granuloma | Chronic lymphocytic « cuffing » pneumonia |
|---|---|---|---|
Core | |||
 Central caseous necrosis of neutrophil origin | + | ++ Multifocal/invasive | Inflammatory cells infiltrate perivascular or close to the bronchioles |
 Extra-cellular bacilli within necrotic core | ++ | +++ | |
 Mineralization | ± | ± | |
Mantle | |||
 Intact and degenerated neutrophils | ++ | +++ | − |
 Macrophages (activated & foamy) | ++ | ++ | + |
 Epitheliod macrophages | ++ | ++ | + |
 Multinucleated giant cells (MGC) | ++ | + | − |
 Lymphocytes | + | + | +++ |
 Cellular bacilli within macrophages and neutrophils | ++ | +++ | ND |
Periphery | |||
 Fibrous encapsulation (Collagenous connective tissue) | +++ | ± | − |
Time of first appearance (post-infection day) [13] | 28 (Circumscribing fibrosis) | 14 (Large, multifocal, numerous bacilli) | 7 |
Bacterial load (CFU) | + | +++ | ± |
Satellite aggregations: neutrophils intact or degenerated | + | ++ | − |