Abstract
Background: Columba livia domestica (domestic pigeon) can contract several infections and parasitic diseases which could potentially cause liver lesions. The avian liver is extremely sensitive to pathology including any changes in circulation, inflammation and haemoparasitism, due to its importance as the main site of metabolism in the body and as the primary organ involved in blood production.
Aim: Gross and histopathological changes in the livers of 20 domestic pigeons were recorded. In addition, smears prepared from blood samples were examined cytologically for the presence of blood parasitic infections.
Materials and Methods: A total of twenty domestic pigeons of different ages and sex were caught from various local places in Mosul–Iraq. Samples of liver of sacrificed birds were examined macroscopically and microscopically after fixing them in 10% neutral buffered formalin. Sections were stained with hematoxylin and eosin (HE) and Giemsa stain. Blood smears were prepared from axillary vein of the examined birds and stained with Giemsa stain to detect hemoparasites. Lesions were scored semi-quantitatively. Measurements were made morphometrically.
Results: There was marked congestion, widespread fatty change, multifocal necrosis and scattered caseous nodules. Areas of severe hepatocellular necrosis, vacuolation, sinusoidal dilation and marked hepatic congestion were seen. Periductal and focal inflammation with bile duct hyperplasia was observed. Widespread parasitism by several haemoparasitic species with different developmental stages was observed. Mixed infections of Haemoproteus and Leucocytozoon and Plasmodium species were seen in blood films.
Conclusion: Domestic pigeons naturally infected with hemoparasites exhibited marked circulatory, degenerative, inflammatory, and necrotic hepatic alterations, highlighting the pathological significance of hemoparasitic infections in avian liver disease.

Key words: Domestic pigeons; Liver lesions; Histopathology; Hemoparasites; Haemoproteus; Leucocytozoon; Plasmodium