Lymphoid Leucosis and Marek’s Disease in Chicken – Gross and Histopathological Studies

Abstract

Study of occurrence of Lymphoid leucosis (LL) and Marek’s disease (MD) in chicken was taken up in Department of Veterinary Pathology, College of Veterinary Science Rajendranagar, Hyderabad.  2,157 birds were presented to post-mortem examination to the department; out of 2157 carcasses, 393 (18.22%) cases showed the lesions of neoplastic conditions; Out of these positive cases, 281 (13.08%) were diagnosed as MD and remaining 112 (5.20%) were LL. These conditions were diagnosed based on gross and histopathological changes. Grossly, diffused enlargement of liver, kidneys and spleen with white foci were noticed in LL; there was enlargement of liver, kidney, spleen, proventriculus and thickening of nerves in MD. Microscopically, diffuse proliferation and infiltration with uniform neoplastic lymphoblast cells were noticed in various visceral organs in LL and pleomorphic in MD.