List of Figures xiii
Fig. 4.4. Distribution of reactor animals disclosed at the beginning of a herd breakdown in PTI 1, 2
and 4 historical testing areas in Great Britain (2003–2005).
Fig. 9.1. Gross pathology of Mycobacterium bovis infection in cattle. (a) Multiple sub-pleural lesions
can be observed in the dorsal part of the right middle lung lobe. (b) After sectioning, multiple
coalescing granulomatous lesions observable with caseous necrosis in the centre and
inflammatory reaction surrounding the areas of necrosis.
Fig. 9.2. (a) Stage I granuloma showing clustered epithelioid macrophages with some Langhans-
type multi-nucleated giant cells (MNGCs). (H&E, 200×) (b) Stage II granuloma with abundant
epithelioid macrophages, visible MNGCs and an incomplete fibrous capsule. (H&E, 100×)
(c) Stage III granuloma showing a complete fibrous capsule and central necrosis. (H&E, 40×)
(d) Stage IV granuloma with a complete fibrous encapsulation, extensive central necrosis and
mineralization. (H&E, 40×)
Fig. 9.3. Acid-fast bacilli within the cytoplasm of a MNGC. (Ziehl-Neelsen, 600×)
Fig. 9.4. CD68+ staining in stage I and II granulomas in the lung of a cow experimentally infected
with M. bovis. Heavy positive staining can be observed within the cytoplasm of macrophages
and multi-nucleated giant cells. (IHC, 100×)
Fig. 9.5. CD3+ staining in stage IV granulomas in the lung of an infected cow with M. bovis.
Abundant positive T cells can be observed mostly in the outer layers of the granulomas. (IHC,
100 ×)
Fig. 9.6. CD79a+ staining in stage I, II and IV granulomas in the lung of a cow experimentally
infected with M. bovis. Scattered CD79a+ cells can be observed within the rim of inflammatory
cells surrounding the necrotic core of the stage IV granuloma and interspersed within the stage
I and II granulomas. The formation of a nest of B cells can be observed in the lesion with a high
number of CD79a+ cells. (IHC, 100×)
Fig. 9.7. Staining of INF-γ in a stage II granuloma from the mediastinal lymph node of a cow
experimentally infected with M. bovis. Abundant IFN-γ positive cells can be observed within the
granuloma. (IHC, 400×)
Fig. 9.8. Staining of TNF-α in a stage IV granuloma from the lung of a cow experimentally infected
with M. bovis. The expression of TNF-α can be observed within the cytoplasm of few epithelioid
macrophages and a multi-nucleated giant cell. (IHC, 400×)
Fig. 9.9. Staining of TGF-β in a stage IV granuloma from the mediastinal lymph node of a cow
experimentally infected with M. bovis. Abundant epithelioid macrophages are expressing TGF-β
within a rim of inflammatory cells adjacent to the necrotic core. (IHC, 40×)
Fig. 9.10. (a) Granulomatous disorganized and diffuse lesion, poorly demarcated within the lung of
a mouse experimentally infected with M. bovis. (H&E, 100×) (b) Abundant AFBs within the
cytoplasm of ‘foamy’ macrophages at the periphery of the granulomatous lesion. (Ziehl-
Neelsen, 600×)
Fig. 9.11. Multifocal granulomas within the lung of a guinea pig infected with M. tuberculosis. The
granulomas are in different stages of development showing solid lesions with no necrosis (small)
and extensive necrosis and fibrotic capsule (large). (H&E, 20×)
Fig. 9.12. (a) Pyogranulomatous severe panniculitis from a cat naturally infected with M. bovis.
(b) Skin lesion from a cat infected with M. bovis, showing extensive dermatitis and inflammatory
cell infiltration in the subcutis, with disruption of the normal epithelium, close to a fistula.
(H&E, 40×) (c) Granulomatous inflammation within extensive necrotic core within the axillar
lymph node. (HE, 40×) (d) Abundant acidfast bacilli within the necrotic centre of the lymph
node. (Ziehl-Neelson, 400×; inset, 1000×)
Fig. 9.13. (a) Detail of the outer layer of a granuloma from the mesenteric lymph node of an alpaca
infected with M. bovis. The necrotic area (upper part of Fig) is surrounded by abundant
inflammatory infiltrate, mostly composed of lymphocytes, a few macrophages and no multi-
nucleated giant cells. (inset) Extensive necrotic core of the lesion. (H&E, 200×; inset 20×)
(b) Few acid-fast bacilli (arrows) are observed within the necrotic centre of the lymph node.
(Ziehl-Neelson, 600×)