This study was performed in cattle in Elazığ Vicinity between February 1995 and March 1996. Initially, serum antibodies against Theileria annulata were investigated by immuno flourescence assays. Furthermore, piroplasm forms of Theileria annulata were investigated in blood smears. The prevalence of specific antibodies was 27.5% (33 /120) and piroplasm forms of Theileria annulata were noticed in 20 animals (16.6%).

At the second stage of the study, 55 seronegative animals were included. In 40 cattle, T.annulata schizont vaccine as administered, and the remaining 15 animals served as controls. Blood samples were collected monthly for a year. In 34 vaccinated animals (85%), antibodies against the antigens of Theileria annulata piroplasm and schizont forms were detected. Nine animals (22.5%) were the carriers of piroplasm forms of T.annulata . In control animals, 8 became positive for antibodies against the antigens of T.annulata schizont and piroplasm forms. These animals were also positive for the presence of T.annulata piroplasms.

After vaccination, seropositivity reduced from the 6 th month and continued until the 12 th month. Antibody titers ranged between 1:20 and 1:2560 for piroplasm antigens and 1:40 and 1:2560 for schizont antigens. In control animals, piroplasm specific antibodies were first detected during May and schizont antibodies during June. The antibody titers in control animals ranged between 1:20 and 1:640 for piroplasm antijens and 1:40 and 1:80 for schizont antijens.

On the animals and in the premises where cattle were housed, Hyalomma.a.anatolicum and H.detritum species were detected. In the examination salivary glands of 212 H.a.anatolicum 10.84% were found to be infected with Theileria annulata. This rate in 16 H.detritum was 6.25%.

It was determined that antibodies against T.annulata schizont and piroplasm were present during the research period in vaccinated and nonvaccineted cattle on which infected ticks were detected.