Table 4.
Distribution and severity of lesions and distribution and intensity of viral antigen staining in tissues of NDV-Peru/08-inoculated birds
| Tissuea | Result on postinoculation dayb: |
||
|---|---|---|---|
| 2 | 3 | 4 | |
| Eyelid | |||
| HE | ++ | ++ | ++ |
| IHC | ++ | +++ | +++ |
| Spleen | |||
| HE | ++ | +++ | +++ |
| IHC | ++ | ++ | +++ |
| Thymus | |||
| HE | + | ++ | +++ |
| IHC | − | ++ | ++++ |
| Bursa | |||
| HE | + | + | +++ |
| IHC | + | ++ | ++ |
| Harderian gland | |||
| HE | − | + | − |
| IHC | − | + | +++ |
| Proventriculus | |||
| HE | + | ++ | − |
| IHC | − | ++++ | +++ |
| Pancreas | |||
| HE | + | − | ++ |
| IHC | − | − | ++ |
| Small intestine | |||
| HE | − | − | + |
| IHC | + | − | ++ |
| Mekel's diverticulum | |||
| HE | + | − | ++ |
| IHC | − | − | ++ |
| Cecal tonsils | |||
| HE | + | ++ | +++ |
| IHC | +++ | +++ | ++++ |
| Large intestine | |||
| HE | − | + | + |
| IHC | − | ++ | ++ |
| Air sacs | |||
| HE | − | − | − |
| IHC | − | − | + |
| Trachea | |||
| HE | − | − | − |
| IHC | − | + | − |
| Lung | |||
| HE | − | − | + (BALT) |
| IHC | − | + (BALT) | ++ (BALT) |
| Pharynx | |||
| HE | + | ++ | ++ |
| IHC | − | + | |
| Brain | |||
| HE | − | − | − |
| IHC | − | − | + (cerebellum) |
| Liver | |||
| HE | − | − | + (MALT) |
| IHC | − | − | − |
| Kidney | |||
| HE | − | − | − |
| IHC | − | − | + |
| Comb | |||
| HE | − | − | − |
| IHC | − | − | ++ |
| Femur | |||
| HE | − | − | + |
| IHC | − | − | + |
HE, hematoxylin and eosin staining; IHC, immunohistochemistry staining for NDV nucleoprotein.
BALT, bronchus-associated lymphoid tissue; MALT, mucosa-associated lymphoid tissue. For HE, the results are scored by tissue as follows: (i) spleen, +, moderate hyperplasia, ++, lymphocytic depletion, +++, moderate (<50%) lymphocyte depletion, histiocytic accumulation, and multifocal necrosis, and ++++, severe (>50%) lymphocytic depletion, histiocytosis, and necrosis; (ii) thymus, cecal tonsil, gut-associated lymphoid tissue (GALT), and bursa, +, mild lymphocytic depletion, ++, moderate (<50%) lymphocytic depletion with necrosis and histiocytosis, and +++, severe (>50%) lymphocytic depletion, necrosis, and histiocytosis; (iii) bone marrow, +, mild (<20%) bone marrow necrosis, ++, moderate (20 to 50%) bone marrow necrosis, and +++, severe (>50%) bone marrow necrosis; (iv) pancreas, +, mild (<3 areas) vacuolation and degeneration, and ++, moderate (>3 areas) vacuolation and degeneration; and (v) brain, +, vascular reactivity, ++, vascular reactivity and perivascular cuffing, and +++, vascular reactivity, perivascular cuffing, and gliosis. For IHC staining, the results are scored as follows: −, no IHC signal detected; +, rare cells in the section are positive on IHC; ++, positive cells seen in <50% of all high-magnification fields (HMF); +++, positive signal seen in 50 to 75% of HMF; and ++++, abundant positive signal in more than 75% of HMF.