Pathological and Immunohistochemical Examinations on Co-Infection with Coligranulomatosis and Marek's Disease in a Turkey Flock

Received : 28/05/2020 Accepted : 21/12/2020 Coligranulomatosis, which induces hepatic granulomas, and Marek's disease, one of the important neoplastic diseases in poultry, rarely causes outbreaks in turkeys. In this study, etiological diagnoses were performed in the light of post-mortem, histopathological, microbiological, and immunohistochemistry studies of turkeys that died in a commercial establishment in the region of Konya. In the post-mortem examination, many grey-white foci with a diameter of 3-10 mm, which sometimes spread from serosa to the parenchyma, were found in the liver. Mucous exudate and hyperemia were detected in all segments of the intestine. For microscopic examination, all tissues were stained with Haematoxylin-Eosin and some selected liver tissues with Periodic Acid-Schiff, Ziehl-Neelsen, and Giemsa. Typical structures of pyogranulomas with an eosinophilic necrotic core in the liver were identified. Tumor foci formed by pleomorphic histiocyte and lymphoid cells were also observed in the liver, spleen, and intestines (jejunum and cecum). In the selected liver and intestinal sections, a positive reaction was obtained in tumor cells in immunohistochemical staining with the primary antibody specific for Marek's disease virus. In addition, Escherichia coli isolation was performed microbiologically in swaps and samples taken from lesioned areas of the liver. As a result of the examinations, other etiological agents that may cause hepatic granulomas in the turkeys were excluded, and coligranulomatosis and Marek's disease were diagnosed simultaneously in this turkey flock. It was concluded that in cases in which these two diseases are observed simultaneously, the diseases might interact with each other, and casualties may increase.