In this study, our aim was to diagnose lymphoid leukosis and Marek's disease, which are neoplastic diseases of chickens, by ELISA and Indirect Immunofluorescence Test (IIF), respectively. Samples (eggs and tissues) were selectively taken from the flocks suspected of having lymphoid leukosis and Marek's disease. The tissues were macroscopically and microscopically examined. Tissues belonging to some flocks showed typical lesions for lymphoid leukosis and Marek's disease. Seven broiler breede flocks and three commercial layer flocks were tested for avian leukosis virus (ALV) group specific antigen (p27) in the albumen. ALV p27 antigen was detected in five out of ten flocks. The rate of ALV p27 antigen positive albumens among the flocks examined ranged from 10 to 42%. The lymphoid leukosis infection rate was found to be 15.06% (36/239 eggs). All the flocks with lymphoid leukosis were broiler breeders and they were 23-33 weeks old. In the diagnosis of Marek's disease, bone marrow smears were used for the detection of MDV antigen by IIF. Of fifteen flocks examined, twelve were determined to be positive. Fluorescent antigen-positive cells were seen in large numbers and these cells exhibited diffuse cytoplasmic staining with discrete granules. Results showed that smears of bone marrow cells are a suitable test material for a rapid and specific diagnosis of MDV infection in chickens. The chickens infected with MDV were 10-20 weeks old.

In this study, our aim was to diagnose lymphoid leukosis and Marek's disease, which are neoplastic diseases of chickens, by ELISA and Indirect Immunofluorescence Test (IIF), respectively. Samples (eggs and tissues) were selectively taken from the flocks suspected of having lymphoid leukosis and Marek's disease. The tissues were macroscopically and microscopically examined. Tissues belonging to some flocks showed typical lesions for lymphoid leukosis and Marek's disease. Seven broiler breede flocks and three commercial layer flocks were tested for avian leukosis virus (ALV) group specific antigen (p27) in the albumen. ALV p27 antigen was detected in five out of ten flocks. The rate of ALV p27 antigen positive albumens among the flocks examined ranged from 10 to 42%. The lymphoid leukosis infection rate was found to be 15.06% (36/239 eggs). All the flocks with lymphoid leukosis were broiler breeders and they were 23-33 weeks old. In the diagnosis of Marek's disease, bone marrow smears were used for the detection of MDV antigen by IIF. Of fifteen flocks examined, twelve were determined to be positive. Fluorescent antigen-positive cells were seen in large numbers and these cells exhibited diffuse cytoplasmic staining with discrete granules. Results showed that smears of bone marrow cells are a suitable test material for a rapid and specific diagnosis of MDV infection in chickens. The chickens infected with MDV were 10-20 weeks old.