Figure 3

Histopathologic results (hematoxylin and eosin staining) in lungs and brains collected from gulls representing groups A–C at 4 and 14 dpi. Example photomicrographs, objective 10x. Lungs, 4dpi: congestion, oedema, fibrinous exudates and moderate necrosis within air capillaries (asterisk) in groups A and B, oedema in group C. Lung, 14 dpi: perivascular lymphoplasmatic infiltrations (white arrows) in groups A, B and C. Brain, 4 dpi, group A: glial nodule; group B: diffuse, moderate gliosis, activated microglia (black arrows), group C: mild gliosis; Brain, 14 dpi, group A: mild gliosis, group B moderate gliosis, aggregates of microglia around blood vessels and neurons; group C, severe encephalitis: there are multiple activated astrocytes visible surrounded by microglia (short arrows), glial nodules (black arrow), and perivascular lymphoplasmatic infiltrates (white arrow). Scale bar = 50 µm.