Diagnosis of Marek’s Disease in Isa Brown Layer Chicken based on Anatomical Pathology and Histopathological Examination

Abstract

Marek’s disease and reticuloendotheliosis are neoplastic diseases in poultry infected by Marek’s disease virus (MDV) and reticuloendotheliosis virus (REV), respectively. This infection may lead to tumor growth in the chicken organ which is difficult to distinguish based on macroscopic lesions, therefore it is important to further diagnose by histopathological examination. Thus, this study aimed to diagnose Marek’s disease in layer chicken based on anatomical pathology and histopathology examination. The samples used were ten cadavers of culled Isa Brown chicken that died in the poultry market. The samples were immediately transported to Pathology Laboratory for necropsy and macroscopically examination. The tumors observed on the pancreas and mesenteric organs were collected and then proceeded to histopathological examination followed by staining using hematoxylin-eosin (HE) and Masson’s trichrome (MT). The anatomical pathology examination showed numerous white-colorized tumors which vary in size found in the mesenteries and pancreas. Histopathological examination demonstrated that tumors consisted of inflammatory cells and reticular cells. The inflammatory cells were pleomorphic and basophilic lymphocytes. In conclusion, in this study, the diagnosis of the visceral type of Marek’s disease in ISA brown layer chicken by means of the anatomical pathology examination was characterized by tumor nodules in the pancreas and mesenteric organs. While microscopically the tumor tissue in Marek’s disease consists of connective tissue and lymphocytes with large cell sizes, varying shapes, and basophilic colors.