Avian leucosis AVIAN LEUCOSIS Avian leucosis is a

Avian leucosis

AVIAN LEUCOSIS • Avian leucosis is a cancerous viral disease of poultry characterized by tumorous growth of blood cells in liver, spleen, lungs, ovary, kidneys and other visceral organs. Disease occurs sporadically in adult birds also known as big liver disease. 2

AVIAN LEUCOSIS Etiology • Avian leucosis virus • Virus has reverse transcriptase enzyme 3

AVIAN LEUCOSIS Pathogenesis • Transmitted vertically from hen to chicks through eggs • Horizontally through direct and indirect contact • It is a malignancy of the bursa-dependent lymphoid system • Metastatic foci in other visceral organs 4

AVIAN LEUCOSIS Characteristic symptoms • Pale comb • Enlarged abdomen • Profuse haemorrhage from feather follicles • Boot like appearance of shank 5

AVIAN LEUCOSIS • Avian leucosis complex includes: • a) Lymphoid leucosis • b) Erythrdblastosis • c) Myeloblastosis • d) Osteopetrosis 6

AVIAN LEUCOSIS a) Lymphoid leucosis • Tumours of lymphoblasts in liver, spleen, ovary and other organs • Tumours are white/grey, raised and glistening 7

AVIAN LEUCOSIS b) Erythrdblastosis • Immature erythrocytes in blood stream, bone marrow and liver • Bone marrow hypertrophied and becomes cherry red in colour 8

AVIAN LEUCOSIS c) Myeloblastosis • Neoplastic growth of granulocytes in liver, spleen and other organs 9

AVIAN LEUCOSIS d) Osteopetrosis • Thickening of the long bones, limbs and ribs due to overgrowth 10

AVIAN LEUCOSIS Microscopic features • Anaplastic blood cells • Malignant cells with mitotic figures 11

AVIAN LEUCOSIS Diagnosis • Symptoms and lesions • Big liver size with tumours • Sporadic occurrence in adult birds • Histopathological examination of affected tissue 12