Avian encephalomyelitis in naturally infected pigeons in Turkey.

The pathological and immunohistochemical findings of avian encephalomyelitis (AE) were described in various tissues of naturally infected pigeons of a flock from a outbreak in Turkey. Clinically, paresis, paralysis, circling movement and torticollis of the head associated with nervous signs were marked symptoms among the diseased pigeons. At necropsy, small or large white-greyish foci were detected in the pancreas, and erosive-ulcerative foci along with petechial hemorrhages in ingluves. Histopathologically, lesions in central nervous system, particularly in the cerebellum molecular layer, consisted of non-suppurative encephalomyelitis. Lesions in the pancreas revealed non-suppurative pancreatitis along with acinar degeneration and necrosis and/or lymphoid aggregations. Immunohistochemical staining of formalin-fixed, paraffin-embedded tissues was performed using a direct-fluorescein antibody technique with chicken anti-AE virus serum fluorescein isothiocyanate conjugate. Viral antigen was strongly stained in cytoplasm of epithelial cells of the exocrine glands, and neurons of the cerebral hemispheres and midbrain. In addition, viral antigen was also marked in the kidneys and tissues of the digestive system. Consequently, this article is, to our knowledge, the first report of natural AE in pigeons.