Molecular characterization of Theileria spp. in cattle in Iğdır region by Nested-PCR method

This study was conducted to determine the prevalence of Theileria spp. and Theileria annulata infections in cattle from Iğdır Province, located in eastern Turkey. Blood samples were collected from a total of 100 clinically examined cattle. Clinical signs suggestive of Theileria spp. infection, such as high fever, lymphadenopathy, nasal and ocular discharge, poor body condition, anemia, and the presence of ticks, were observed in 39 of the animals. Microscopic examination of Giemsa-stained blood smears revealed intraerythrocytic piroplasm forms in 22% of the cattle. In conventional PCR analysis using Theileria spp. specific primers (989a/990a), specific 1098 bp amplicons were obtained in 39 samples. Subsequent nested PCR using N516/N517 primers confirmed T. annulata positivity in 30.76% of the clinically suspected samples, producing specific bands of approximately 721 bp. These findings indicate a significant presence of T. annulata infection in the study area. DNA sequencing and BLAST analysis were performed on two positive isolates. Phylogenetic analysis based on the Tams1 gene region showed that the isolates obtained from Iğdır clustered within the same clade as isolates from Iran and Pakistan, displaying a high degree of genetic similarity. This suggests that the circulating T. annulata strains in the region are evolutionarily closely related to foreign isolates, with limited local variation. Importantly, this study represents the first molecular and phylogenetic characterization of Theileria annulata isolates from cattle in the Iğdır Province.