Location: Endemic Poultry Viral Diseases ResearchTitle: Two cases of Marek's disease in backyard turkeys
Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2020
Publication Date: 3/18/2020
Citation: Hauck, R., Mays, J.K., Dunn, J.R., Shivaprasad, H.L. 2020. Two cases of Marek's disease in backyard turkeys. Avian Diseases. 64(3):347-351. https://doi.org/10.1637/aviandiseases-D-19-00177.
Interpretive Summary: Two non-commercial turkeys were submitted for necropsy and found to have tumors in the liver, spleen, kidneys and gonads. Microscopic examination confirmed presence of tumor cells, and virus specific assays were used to diagnose Marek's disease. In both cases, turkeys were co-mingled with chickens, which were the likely source of infection. Although Marek's disease has been diagnosed in turkeys in other parts of the world, this is the first definitive case report in the US.
Technical Abstract: In two independent submissions, a three year old, dead Bourbon Red turkey tom from a zoo and a Royal Palm turkey hen from a backyard flock were submitted for necropsy. Both birds had been kept together with chickens. Findings of the necropsy of the first turkey were enlarged and dark liver with many pale white foci and a few small white nodules; pale and enlarged spleen; prominent thymus; mottled and pale kidneys, pale and enlarged testes. Findings of the necropsy of the second turkey were dark and mildly enlarged liver and severely enlarged, firm and pale kidneys. Histopathology revealed infiltration of most organs of both birds with neoplastic lymphocytes, which were uniform in the first turkey and pleomorphic in the second turkey. Immunohistochemistry identified the neoplastic lymphocytes as T-cells by CD3 marker. Marek’s disease virus serotype 1 was detected by PCR in livers of both birds, while PCRs for reticuloendotheliosis virus and lymphoproliferative disease virus were negative. Based on these findings MD was diagnosed in both turkeys, which is very rare and the first definitive case report in the US. It is probable that the chickens were the source of infection.