Marek’s disease outbreak in adult Rajasri layer chicken

Abstract

Marek’s disease was diagnosed upon routine postmortem examination conducted at Department of Veterinary Pathology, College of Veterinary Science, Hyderabad. There was a sudden mortality of about 6-8 birds per day in 12 weeks old Rajasri chicken. Clinically, birds showed weakness, diarrhoea, pale comb and mortality of 70 birds out of 220 birds (31.8%) for a period of one week. Upon necropsy examination, gross lesions observed were hepatomegaly, splenomegaly, thickening of proventriculus and multiple greyish white nodular growths on proventriculus, liver, intestines and pancreas. Impression smears of liver prepared for cytological examination. Impression smears from liver were prepared for cytological examination. Impression smear of liver and Histopathological examination of liver, spleen, pancreas and proventriculus revealed numerous proliferating pleomorphic lymphocytes which is suggestive of Marek’s disease.